US1174262A - Telephone system. - Google Patents

Description

E. H. MARTIN 1 T. H. FERGUSON.

TELEPHONE SYSTEM.

APPLICATION FILED JAN. 26. 1914.

Patented Mar. 7,1916.

2 suns-511mm THE COLUMBIA PLANOGRAFH co., WASHINGTON. B. c.

. E. H. MARTIN & T. FERGUSON.

TELEPHONE SYSTEM APPLICATION FILED JAN. 26

I m4 Patented Mar. 7, 1916.

2 SHEETSSHEET 2 THE COLUMBIA PLANOGRAPH 510., WASHINGTON, D c.

en in ears PATENT EDWARD r1. MARTIN, or WEBSTER oI'rY, IOWA', AND THOMAS H. FERGUSON, or OAK PARK, IL INOIS; SAID FRRGUson ASsIGNOR fro SAID MARTIN. V

TELEPHONE SYSTEM.

specificationpf Letters'Patent.

Patented Mar. 7, 1916.

Application filed January 26, 1914. Serial No. 814,358.

ll ebster City, county of Hamilton, State of Iowa, and at Oak Park, county of Cook,

State of Illinois, haveinvented certain new and useful Improvements in Telephone Systerns, of which the following is a specification.

The present invention relates to telephone systems and has for its object to provide means for indicating to subscribers or operators when conversation has reached or exceeded a given period of time.

It is common practice among telephone companies to allow a conversation of a definite extent, say 3 minutes, for a certain rate, and then to charge a different rate from that time on, to cover the balance of the conversation. By theuseof the present invention the normal time limit, say 3 minutes, is indicated to the conversing parties directly, or to an operator, who may then notify the conversing parties.

The invention is especially applicable t toll line practice where accurate supervision and an accurate record of the time of conversation is necessary.

The invention may be applied to various types of telephone systems and may be variously arranged for any given type. Its various applications and embodiments will be apparent in the following detailed description taken in connection with the accompanying drawing, while the scope of the invention will be apparent from the appended claims.

In the drawing Figure 1 is a diagram of a telephone system constructed in accordance with the present invention, and illustrating particularly the application of the invention to toll line practice; Fig. 2 illustrates a modified control circuit for the indicating device; Fig. 3 illustrates a modified contact control for use in setting the indicating mechanism into operation; Fig. 4 is a diagram of a multiple common battery system constructed in accordance with the present invention; Fig. 5 illustrates a modified form of indicating device and control mechanism for use in various systems; and Fig. 6 is a diagram of a telephone system having still further modifications of the indicating mechanism and control circuits.

Throughout these views like characters refer to'lik'eparts.

Referring to the drawing in detail and more particularly for the present to Fig. 1, A designates a common battery substation connected by line limbs 10. and 11 to an eX- change; designates a local battery substation, similarly connected by toll line limbs 12 and 13 with the same or another exchange; 0 designates a trunk circuit by which the trunk operator may make connection w th the common battery line; D-designates a cord circuit by which the toll operator may connect the trunk with the toll line; and E designatesathe indicating device by which supervision of a conversational circuit between substations A and Bis had: The substation A- is provided with the usual transmitter 14, receiver 15, condenser 16, induction coil 17, switch-hook 18 and call-bell 19. The condenser 16 and bell 19 are normally in bridge of the line limbs through the lower switclrhookcontacts. When the receiver is removed, the transmitter 14 and induction coil 17are brought into bridge of the line limbs, the induction coil being in parallel withthe branch through the condenser 16and receiver 15. The substation B is similarly equipped with atransmitter 20, local battery 21, induction 'coil 22, re ceiver 23, switch-hook 24 call-bell 25, and hand generator'26. The call-bell 25 is normally in bridge of the line through the lower switch-hook contact. When the receiver 23 is removed fromthe switch-hook 24' the transmitter 23, battery 21 and one winding of the induction coil 22 arebrought into a local circuit in inductive relation to the line circuit which includes the other winding of the induction coil22 and receiver 23. When the generator 26 is operated, the callbell 25 is cut out of circuit and the generator replaces it in bridge of the telephone line. The common battery line is providedat the eXchange with a cut-off relay 27, a line relay 28, a line lamp 29, multiple jacks 30 and connection to battery 31. The toll line is provided at the exchange with aline relay 35, a cut-off relay 36, line lamp 37, multiple jacks 38, busy lamps 39,.protective resistance 40 and connection tobattery 41. The trunk C includes a plug 46, a ringing relay 47, sleeve relay 48, tip relay 49, signal lamps. 50, 51, sleeve relay 52, trunk relay 53, re-

peating coil windings 55, 56, 57, control i relay 58, condensers 59, 60, 61, and jacks 62.

A battery 63, protective resistance 64, and

ringing generator 65 are associated with,

key contacts 70, 71, 72,73, supervisory relays 74, 75, control relays 76, 77, ringing key contacts 78, 79, ringing generator 80, talking strand condensers 81, 82, a connection to battery 83, and supervisory lamps 84, 85. The positions of the trunk and toll operators are united together by an order wire 86 extending from the trunk operators head set 87 to the toll operators head set 88 through contacts 89 and 90 of a control key. The indicator E by which a conversational circuit through the cord circuit D is supervised, includes relays 91, 92, control contacts 93, 94, 95, a delay device 96, a switch 97, and an indicating lamp 98.

' In the operation of the system of Fig. 1, the connection is always to proceed from the toll operator to the trunk operator and thence to the local line wanted. The toll operator may receiveher order from a calling toll subscriber or from a recording operator who has received an order from a calling local subscriber. Assuming that the call comes from a toll subscriber, then it will be observed that when the party operates his generator 26 to initiate a call, a circuit will be completed for the generator current over line limbs 12 and13 through the upper winding of line relay 35 and closed contacts 99 of cut-ofl relay 36. The flow of generator current over this circuit energizes line relay 35 and causes it to close its normally open contact 100. As a result, line relay 35 is locked up by a circuit which may be traced from the live pole of battery 41 through the lower winding of relay 35, closed contact 100 of relay 35 and closed contact 101 of relay 36 to ground. The closing of line relay contact 100 also closes a circuit for line lamp 37, which may be traced from the live pole or battery 41 through protective resistance 40', line lamp 37 and closed contacts 100 and 101 to ground. The closing of contact 100 also completes a circuit for busy lamps 39, which may be traced from the live pole of battery 41 through lamps 39 in parallel, normal contact 102 of cut-off relay 36 and thence through closed contacts. 100 and 101 to ground. The lighting of line lamp 37 indicates to the toll operator that the party at substation B has initiated a call. The lighting of busy lamps 39 indicates to operators at other positions of the multiple board that the line from substation B is busy and not in condition to be connected to as a called line.

The operator upon observing the lighted lamp 37 inserts the plug 67 of one of her cord circuits D into the answering jack 38 of the line calling. As a result of this act, control relay 77 and cut-ofi relay 36 are energized over a local circuit which may be traced from the live pole of battery 83 through the winding of relay 77, conductor 103, plug and jacket contacts, and the winding of cut-oil relay 36 to ground. The energization of relay 77 closes part of a locking circuit for relay at its contact 104. This locking circuit, however, does not come into operation until the time of release. The energization of cut-off relay 36 disconnects the upper winding of relay 35 from the line at contact 99. Such energization also opens contact 101 and thereby opens the circuit for line lamp 37 and causes its extinguishment. The same opening of contact 101 opens the initial circuit for busy lamps 39 but a substitute circuit is closed for these lamps by the energization of relay 36 through alternate contact 102 to ground. Thus-the busy lamps are maintained lighted during the energization of the cut-off relay. The next act on the part of the operator is to actuate her listening key to close contacts 70 and 73 to bring her operators set 88 into bridge of the talking strands 105 and 106 and thus into circuit through plug and jack contacts with the calling line. Upon conversing with the calling party and obtaining his order, the toll operator next actuates her order wire key to close contacts 89 and to bring her telephone into circuit with the telephone set 87 of the trunk operator in order to have a trunk assigned for the connection. The trunk operator also receives the number ofthe local subscriber wanted and after assigning a trunk proceeds to connect that trunk to the local subscriber wanted. The toll operator having been assigned a trunkfor the connection inserts the plug 66 of her cord circuit into jack 62 of the assigned trunk. The trunk operator likewise inserts the plug 46 of the assigned trunk into multiple jack 30 of the called-for line. This latter act operates sleeve relay 48 and cut-off relay 27 over a local circuit which may be traced from the live pole of battery 63 through the winding of relay 48 over the sleeve side of the circuit, through plug and jack contacts, and the winding of cut-ofi? relay 27 to ground.

The operation of the cut-off relay disconnects line relay 28 and extends the line limbs 10 and 11 to the jack terminals. The application of current to the sleeve terminals of the jacks 30 also places a busy potential upon them for test purposes. Before inserting the plug 46, the trunk operator would test the called-for line by touching the tip of her plug 46 against the sleeve contact of the jack, and, in case the line was busy, there would be momentary flow of current from the tip of the plug through normal contact 107 of ringing relay 47, normal contact 108 of sleeve relay 48, and the tertiary winding of the induction coil of the operators telephone set 87 to ground. This momentary impulse of current would produce a click in the operators receiver, as an indication to her that the line was in use. However, having found the line idle, and having in serted the plug 46, relays 48 and 27 are actuated over the local circuit traced. The energization of relay 48 actuates its contact 108 to open the path just traced through the tertiary winding of the operators set 87 and to close the talking strand 109 of the trunk C at this point. The energization of relay 48 also closes contact 110 and thereby energizes relay 53 over a path which may be traced from the live pole of battery 63 through the winding of relay 53, closed contact 111 of tip relay 49, and closed contact 110 to ground. Similarly, a path is closed through contacts 110 and 111 for signal lamp 50, which is consequently lighted. A path is also closed through these same contacts and normal contact 112 of relay 52 for lamp 51. This lamp is lighted in response to the closing of this circuit but this circuit will be interrupted by contact 112 upon the energization of relay 52, which occurs as soon as relay 53 is operated, provided that plug 66 has been inserted in trunk jack 62,

or upon. the insertion of such plug intothe jack, in case such operation takes place sub sequent to the energization of relay 53. The

' circuit for relay 52 extends from the live shows the trunk operator that the toll operator has plugged into the jack of the trunk assigned. The closing of this circuit also actuates relay 74 to close a circuit for its lamp 84 through closed contact 117 and listening key contacts 71 and 7 2 to ground.

As we shall see, this lamp remains lighted until the called-for party responds and operates relay 49 to open the circuit of relav 53, and thus open the circuit of relay 74. When the toll operator sees lamp 84 light, she knows that the trunk operator has completed the connection to the called-for partys line. The toll operator then depresses her ringing key to ring the calledfor party. As a result of this act, the generator S0 is brought into circuit with the trunk conductors 114 and 115 at alternate contacts 68 and 69 of the ringing key. Current then flows from the live pole of the generator through alternate contact 68, plug and jack contacts, conductor 115, repeating coil winding 56, there dividing, part going to ground through closed contact 116 of relay 53 and impedance coil 118, and part returning to the opposite pole of the generator through the winding of. relay 58, con denser 61, repeating coil winding 57 trunk conductor 114, plug and jack contacts, and

alternate contact 69 of the ringing key. -As

a result of the closing of this latter branch, relay 58 is energized and held energized during the depression of the ringing key and by its contact 119 closes a circuit for ringing relay 47 from the live pole of battery 63. The resulting actuation of relay 47 moves its contacts 107 and 120 to their alternate positions and thereby applies ringing current directly to the called-for line. The complete ringing circuit extends from the live pole of the generator over one side of the line through the bell at the substation and back over the other side of the line through protective resistance 64 and battery 63 to the opposite generator pole.

When the called-for party responds by removing his receiver from its hook, a path for current in shunt to the cut-ofi relay 2'? is provided through the line limb 11, substation impedance coil 17, switch-hook contacts, transmitter 14, line limb 10, plug and jack contacts, normal contact 107, trunk strand 109, alternate contact 108 of relay 48, and the winding of tip relay 49 to ground. The closing of this path energizes relay 49 to open the circuits for lamps 50 and 51 and relay The extinguishment of lamp 50 shows the trunk operator that the called for party has responded. Lamp 51 also remains extinguished at this time. The deenergization of relay 53 opens the circuit of the left hand winding of relay 74, and said relay releases its armature and extinguishes lamp 84 as an indication to the toll operator that the called party has responded. The subscribers lines are now connected for conversation. The transmitter 14 of the common battery line is energized by current from battery 63, while the transmitter 20 is energized by the local battery 21. The talk ing circuit is indicated by heavy lines. e

As soon as the talking circuit is completed, the toll operator, who has supervision of the connection, actuates the indicating device E by pressing downward upon the key 121 to force contact 93 into engagement with contact 94, and then the latter into engagement with contact 95. The contacts 93 and 94 are springs which normally lie in the position illustrated, but which yield under the pressure to bring about the connections just described. -The restoration of the contacts 93 and 94 to their normal position is retarded by the retarding device 96, which is here illustrated in the form of a dash-pot directly connected to the outer end of the spring. con

&

I tact 93. The contacts 93, 94c, 95, are preferably supported in-a block of insulation 122. The first circuit closed upon depression of the key 121 is a circuit for relay 91. It may be traced from the live pole of battery 83 through protective resistance 123, the winding of relay 91 and closed contacts 95 and 94 to ground. The closing of this circuit energizes relay 91, which immediately locks itself up through a branch including closed contact123; closed contacts 93 and 94: to ground. These la ter contacts remain in engagement until just prior to reaching their normal position. Due to the retarding device 96, this does notoccur until a definite, time interval has elapsed from thetime the key 121 was first depressed. This period is the initial conversation period, which is usually 3 minutes. At the conclusion of this period, as we shall see, the indicator lamp 98 is lighted to advise the operator that the parties are talking in excess of the minimum limit.

Besides closing its locking circuit, relay 91, upon its energization, closes a circuit for theleft-hand winding of relay 92, which may be traced from the live pole of battery 83 through protective resistance 123, alternate contact 124:, the left-hand winding of relay 92 to manual switch 97. This switch is arranged to cut in either or both of two branches which extend from its contacts to ground, in the one case through normal contact 125 of relay 75', and in the other case through normal contact 126 of relay 7 1'. It

may be assumed that the manual switch 97 is p in position to close both of these branches. As a result of closing this circuit, relay 92 closes its contacts 127 and 128. The latter completes a locking circuit for relay 92 through its right-hand winding. As a result of this arrangement, relay 92 is locked'up until both of the relays 7i and 7 5', under the assumed position of manual switch 97, are actuated, while relay 91 remains actuated during the definite time interval previouslv referred to. 'At the expiration of this time interval, indicating lamp 98 is lighted over a circuit extending from the live pole oi battery 83 through protective resistance 123, normal contact 12 1 of relay 91, closed contact 127 of relay 92, and lamp 98 to ground. The lighting of this lamp, as before stated, is an indication to the operator that the normal period for conversation has expired, and that the parties should be notified of this fact. She does this by operating her listening key contacts 7 0 and 7 3 to bring her tele phone set 88 into circuit and then speaking directly to the parties. 7

At the conclusion of conversation, the party at substation B restores his receiver to its hook and gives his generator 26 a turn which sends generator current over both sides of the talking circuit through the right-hand winding of relay 75. As a result relay 75 is energized and locked up. The locking circuit extends from the live pole of battery 83 through closed contact 104 of relay 77, the left-hand winding or relay 7 5, closed contact 129 of relay 75, and listening key contacts 72 and 71 to ground. The closing of contact 129 also brings the lamp 85 into circuit and lights it. The restoration of the receiver at substation A interrupts the path for current to the tip supervisory relay 19 and causes it to close its contact 111 to bring the lamp 50 and relay 53 again into circuit, through the closed contact 110 of sleeve supervisory relay 48. As a result, lamp 50 is lighted as an indication to the toll operator that the called-for party has restored his receiver to its hook. As a further result, relay 53 is again energized and relays 52 and 7 1 again brought into circuit and operated. The operation of relay 52 prevents the lighting of lamp 51. The operation of relay 74- lights lamp 84. Both lamps 8-1 and 85 now being lighted, the toll operator takes down the connection by removing the plugs 66 and 67 from their jacks. As a result, all the parts of the cord circuit are restored to normal. Also, the removal of plug 66 opens the circuit of relay 52 and causes its contact 112 to close the circuit of lamp 51, which is consequently lighted. Both lamps 50 and 51 being lighted, the trunk operator now withdraws the plug 46 from the jack of the called line, thus leaving the trunk and line circuit of the called line, with their several relays, in normal position. All the parts are now in condition tor a subsequent operation.

It will be noted that when the manual switch 97 of the indicator E closes both branches to ground through contacts 125 and 126 of relays 75 and 74, respectively, relay 92 will not have its locking circuit opened until both relays 7 1 and 75 have been energized. Consequently, indicator lamp 98 will not go out until both relays 7 1 and 75 have been energized. In contrast to this, if the manual switch 97 includes only one of the branches, then the lamp 98 will be extinguished when the corresponding relay, 74 or 75, is energized. It will be apparent that the control circuit for this relay 92 of the indicator E might be differently connected through contacts of relays 7A and 75.

In Fig. 2, a modified arrangement is shown, in which the control circuit extends through the contacts 126 of relay 7 1, and 125 of relay 75, in series instead of in parallel branches as illustrated in Fig. 1. Other arrangements will also suggest themselves to those skilled in this art. It is also apparent that the contacts 93, 94- and 95, might be electrically operated instead of being manually operated, as is the case in the embodiment of the invention illustrated in Fig. 1.

In Fig. 3 these contacts are actuated by the armature 130 of an electro-magnet 131, whose winding is included in circuit with a battery 132 and a control key' 133. In practice, the keys 121 or, 133, as the case may be, are located on the switch-board in line with the corresponding ringing and listening keys, and the indicator lamp 98 is in similar alinement and association with the supervisory lamps 8-1 and 85. As a result, the operator can determine readily the circuit whose indicator is to be operated and whose indicating lamp is lighted.

In the above description of the form of the invention illustrated in Fig. 1, the co1nplete connection was put through in response to a call from a toll subscriber. If a local subscriber calls for a toll subscriber, then the removal of his receiver operates his line relay 28 and lamp 29, and his call is answered over circuits not shown in this diagram, and'his order commmunicated to a recording operator. He then restores his receiver to its hook and waits to be called. The order received by the recording oper ator is passed on to a toll operator, who calls the desired toll subscriber. This is done by inserting plug 67 into jack 38 of such line, when the busy lamp shows it to be idle. This act pulls up the cut-off relay 36, which disconnects the line relay 35 from the line, disconnects line lamp 37, and lights the associated busy lamps 39 as before explained. The operator then rings the toll subscriber by actuating the contacts 78 and 79 of her ringing key and thereby closes a circuit from the live pole of the generator 80 through alternate contact 7 8, plug and jack tip contacts, line limb 12, call bell 25, line limb 13, plug and ack sleeve contacts, alternate contact 7 9 of the ringing key to ground. 8 When the called party at substation B responds by removing his receiver, the operator communicates with him through the agency of her listening key and head set 88 and then proceeds to put through the connection to the original calling party at substation A, in the manner before explained. Before passing on to the systems of the remaining figures, it may be pointed out that the trunk operators head set 87 comprises an induction coil 134 having three windings. One of these is included in the grounded branch normally closed at back contact 108 of sleeve relay 48, as before explained. A. second winding is included in series with a receiver 135 in the main circuit of the order wire. The third winding is included in series with condenser 136, battery 137 and impedance coil 138. The transmitter 139 is connected so as to close a local circuit with the impedance coil and battery, one terminal of the coil being grounded as illustrated. The toll operators telephone set 88 includes a similar i arrangement of battery 140, impedance coil denser 1&1, transmitter 142, condenser 1&3 ,andone winding of an induction coil 144:. The other winding of the induction coil is included in series with a receiver 145 and condenser 1&6

in connections adapted to place the same in bridge of the talking circuitupon the operation of the associated listening key.

In Fig. 4: a somewhat different embodiment of our invention is shown in associa- Each substation is provided with a con- 202 and call-bell 203 in normal bridge of the line, and a transmitter 204 and receiver 205 for inclusion in bridge of the line when the receiver is removed from its switch hook 206. At the exchange each line is provided with a line relay 207, line lamp 208,. cut-off relay 209, and multiple jacks 210, the line relay being connected normally in circuit with the line and bat tery 211. Cord circuit H comprises plugs 212 and 213 connected by strands 21 1 and 215 having interposed condensers 216 and 217 This circuit is of the lt-relay type, including sleeve relays 218, 219, tip relays 220, 221,- supervisory lamps 222, 223and a connection to battery 224C. The indicating device in this diagram is designated generally by the letter I and includes contacts 225 and 226, a retarding device 227, a manual switch 228, and indicator lamps 229 and 230. In operation, a party calling from substation F, for example, removes his receiver from its hook and thereupon closes a circuit for line relay 207, which results in lighting line lamp 208, asan indication to the operator that such party desires to make a call. The operator thereupon inserts plug 212 into answering jack 210 and completes a circuit for relays 218, 209 and 220, which may be traced from the live pole of battery 22 1 through the winding of relay 218, strand 215, plug and jack sleeve contacts, to the lower contact, 231

of cut-0E relay 209,. there dividing, part going to ground through the winding of cut-01f relay 209, and the other part continuing over the line limb 201 through the substation and back over line limb 200, al-

. ternate contact 232 of cut-0E relay 209, plug and jack tip contacts, strand 214: and the winding of relay 220 to ground. As a result of the energization of cut-0E relay 209, line relay 207 is disconnected from the line and a busy potential is put upon the sleeve contacts of the multiple jacks 210 to guard the line against connection. The energization of relays 218 and 220 closes a circuit for lamp 222 at contact 233 and opens the same at contact 234. The energization of these relays also closes a circuit for indicator lamp 229 at contacts 235 and 236. if

the manual switch 218 be in position to conthrough contacts 225 and 226 to ground, and

lamp 229 will be lighted.

After the operator has depressed her listening key contacts 237 and 238 to include her telephone set 239 in circuit with the calling party, she may converse with the calling party and receive his order. Upon receipt of this, she tests the called-for line by touching the tip of her plug 213 against the sleeve contact of a multiple jack 210 and, in case the line is busy, receives a definite .click in her receiver as an indication that the connection cannot be made. In case the line is idle, the operator inserts plug 213 into jack 210 and thereupon closes a circuit for sleeve relay 219 and cut-off relay 209 over the sleeve side of the clrcult,

as before traced in connection with relay 218 and cut-oil relay 209 of the calling line. The energization of relay 219 closes a circuit for supervisory lamp 223 at contact 240.

This causes the illumination of lamp 223.

At the same time contact 241 closes a portion of the circuit for indicator lamp 230 but this circuit is openat this time at contact 242 of tip relay 221. The other contact 243 of tip relay 221, as before noted, leaves the circuit'of lamp 223 closed. Upondepressing her ringing key contacts 244 and 245, the operator includes the generator 246, protective resistance 247 and battery 248 in circuit with the called-for line, and thereby rings the call-bell 203 of the calledfor line. Upon the response of the called-for party the tip supervisory relay 221 is energized by current over the line and tip side of the cord circuit, through the winding of said relay to ground. The energization of relay 221 opens the circuit of supervisory lamp 223 and causes its extinguishment. It also completes the circuit for indicator lamp 230, Which, under the assumption we have heretofore made, is illuminated. The two parties are now able to converse over the heavily marked talking circuit. As soon as this condition is reached, the operator depresses the key 249 of the indicating device I and opens the circuit for indicator lamps V 229 and 230. The return of the contacts 235 and 236 into engagement is delayed by and, all the cord circuit relays being energized, close the circuit for the indicator versational circuit of the subscribers and At the conclusion I notify them of this fact. of conversation, the restoration of the receivers at the substations opens the circuits for the tip relays 220 and 221 with the result that supervisory lamps 222 and 223 are lighted. This operation also extinguishes indicator lamps 229 and 230. The lighting of lamps 222 and 223 is an indication to the operator to take down the connection. The withdrawal of the plugs 212 and 213 deenergizes the sleeve relays 218 and 219 and the cut-off relays 209,'and all the parts are thereupon restored to normal, in condition for use in response to subsequent calls.

Before passing on to the other figures, it

may be pointed out thatthe operators set is the same in circuit arrangement as the operators set 88 of Fig. 1.

In each of the applications of the invention heretofore described notification at the end of the normalconversational period has been given to the operator. In carrying out our invention, however, the indication at this time may be given directly to the conversing parties without the services of the operator. In Fig. 5 an arrangement of apparatus and circuits is provided to bring about this result. In this figure one of the strands of the talking circuit, such as the strand 215 of the cord circuit of Fig. 4, normally extends through normal contacts 300 and 301 of a control relay 302, which is arranged to be included momentarily in cirto hold contacts 304 and 305 out of engagement. A retarding device 308 is connected to contact 306 and is operative to prevent its rapid downward movement. A retarding device 309 similarly acts upon contact 307 to prevent its rapid upward movement. lVhen relay 302 is energized its contacts 300 and 301 bring the secondary winding of a transformer 310 directly intocircuit with the talking strand, as 215, with which the indicating device is associated. The primary Winding of the transformer 310 is included in circuit with an alternating current generator 31.1. In the operation of this mechanism the operator depresses key 312 so as to force contact spring 307 downward to its full extent. She does this as soon as the conversation between the parties begins, as heretofore. The first efl'ect of this clownward movement is to separate contacts 306 and 307. Contact 306, being retarded by the retarding device 308, cannot maintain engagement with contact 307 as it is moved downward. It does, however, later engage contact 305, where it rests until contact 307 upon its up ard return movement engages it. Then, by reason of the greater tension in the contact 307, contact 306 is forced out of engagement with contact 305, and ultimately restored to the position illustrated. As soon as contact 307 in its return movement engages contact 306, which in turn is in engagement with contact 305, a circuit is completed through the control relay 802. This circuit is of short duration because of the continued upward movement of contact 807, which opens the circuit by separating contacts 305 and 806. The momentary energization of relay 302, however, is suflicient to bring the secondary winding of the transformer into the talking circuit and produce a sound or indication in the receivers of the conversing parties which announces to them that the normal time allowed for conversation has elapsed. I This indication does not persist longer than relay 302- remains energized. Since the circuit of said relay is momentary only, the indication is also momentary only. It will be apparent that in applying this indicating device to existing circuitsgit may be applied in any strand of a conversational circuit adjacent to a condenser, or in any such strand where it is not necessary to maintain a flow of current for other purposes than for conversation. It is also apparent that it may be interposed in circuitswhere current is thus required by properly providing an alternate path during the period of energization of the relay 302. These i mssibilities will readily occur to those skilled in the art when the circumstances of a particular circuit are in view.

In the indicating mechanism lust de ated at the proper time, while that at the right is provided with a lamp which is lighted at the proper time and remains lighted until the conclusion of conversation. The line and cord circuits of the system to which these modifications are applied are the same asthose illustrated in Fig. 4 and the corresponding parts are designated by the, same numerals. For convenience, however, the station at the left is designated L, that at the right M,-the cord circuit N, and the indicating device 0. At the substation L the indicating device consists of a drop 400 having a core 401, windings 402 and 403, an angle armature 404 and a shutter 405. The windings 402 and 403 are wound side by side upon the core 401 and each is included in circuit with one of the linelimbs, the winding 402 with line limb 200, and the winding 403 with line limb 201. An impedance coil 406 is also associated with these line limbs at the substation L. Its core 407 is provided with two similar " parallel windings 408 and 409. The righthand end of the winding 408 is connected directly to line limb 200, while the left-hand end of the winding 409 is connected through a contact of the switch-hook to the line limb 201. The opposite ends of the windings 408 and 409 are connected to ground. At substation M a relay 410 takes the place of the drop 400 of substation L. This relay has a core 411 and windings 412 and 413, arranged in series with the line limbs, just as in the case of the windings of drop 400. An imped ance coil 412, similar to the coil 406 has its windings 413 and 414 connected to the line limbs, the former winding directly to line limb 200 and the latter to line limb 201 through normally open contacts of the switch-hook. As in theprevious case, the left-hand terminal of one of these windings is connected to one line limb and the righthand terminal of the other winding to the other line limb, while the opposite terminals are connected to ground. In this case relay 410, by its contact 415, controls'a circuit from battery 416 through the lefthand winding of relay 417. A locking circuit through the right-hand winding of relay 417 is closed by its contact 418 through signal lamp 419 and normally open contacts 420 and 421, which are held open when the receiver is upon its hook, but which move into engagement under their inherent tension when the receiver is removed fro .1 its hook.

The indicating device 0 includes contacts 422, 423 and 424, which are controlled in their operation by a key 42-5 and retarding devices 426 and 427. These contacts may also be controlled when desired by an armature 428 of a magnet 429, which is under the control of cord circuit relays. In moving the contacts the armature engages an insulating projection 430 to draw the contact sprin g 424 downward. The same result may.

be produced by pressing upon the key As the spring 424 moves downward it first breaks contact with spring 428, which gradually moves downward under the retarding action of its delay device At the lower end of its movement, contact spring 423 engages contact spring 422. When contact spring 424 is free for movement it moves upward under its tension into engagement with contact spring 423 and forces the latter upward to the position illustrated. A battery 431 is connected through a protective resistance 432 with the contact 422. The contact 424 is connected through a manual switch 433 to two parallel branches which extend through control relays 434 and 435. Either one, or both, of these control relays may be brought into circuit by properly positioning the manual switch433. The operation of relay 434 connects battery 431 to both sides or" the talking circuit at'the lefthand end of the cord circuit, through its contacts 436, 437 and an impedance 0011 438. The operation of relay 435 connects the same battery to both sides of the talking circuit at the right-hand end of the cord circuit, through its contacts 439 and 440, and the connection includesimpedance coil 441. The impedance coil 438 has two parallel windings 442 and 443 arranged upon the same core and having their terminals oppositely connected, the left-hand terminal of the winding 442 and the right-hand terminal of the Winding 443 being connected to the relay contacts, and the opposite terminals of the windings to the live pole of the battery 431. In the case of impedance coil 441 the left-hand terminal of the winding 444 and the right-hand terminal of the winding 445 are connected to the live pole of the battery 431 and the opposite terminals are connected to the relay contacts. The circuit of magnet 429 extends through a manual switch 446, normally closed contact 447 of tip relay 221, andnormally open contact 448 of sleeve relay 219 to the live pole of battery 224. When the indicating device 0 is to be operated manually only, the switch 446 is left in open position. When automatic operation is desired this switch is left in its closed position.

In operation the party at substation L removes his receiver to initiate a call and thereby closes a path for current through his line relay 207 which may be traced from the live pole of battery 211 through the winding of relay 207, normal contact 231,

line limb 201, winding 403, switch-hook 206, receiver 205, transmitter 204, winding 402, line limb 2 0, normal contact 232 to ground. A path to ground also exists through a branch including the winding 409 of impedance coil 4 A second path to ground also extends through the winding 408 of the impedance coil 406. The impedance coils 406 and 412 are of high ohmic resistance and consequently the flow of current through these paths is slight and does not shunt suflicient current from the Winding 402 of drop 400 to cause its operation. As will be seen under this. circuit condition, the flow of current through one winding of the drop 400 is opposed to that through the other winding so that the, core 401 remains practically neutral. Upon the lighting of the line lamp 208, the operator answers by inserting plug 212 into the answering jack 210 of the line from substation L and thereupon operates the sleeve relay 218, cut-ofi' relay 209 and the tip relay 220, in the manner explained in connection with the description of Fig. 4. Again the flow of current through the windings of the drop 400 leaves the core practically neutral and the drop in its normal condition. The operator then listens into the circuit by operating her listening key contacts 237 and 238 and, upon learning the order of the calling party, in-

serts plug 213 into jack 210 of the desired line, which for the present may be assumed tobe the line leading to substation M. This act on the part of the operator energizes sleeve relay 219 and cut-off relay 209, as explained in connection with the description of Fig. 4. The operator then depresses her ringing key to actuate contacts 244 and 245 and ringing current thereupon passes out over the tip side of the line through the winding 412 of relay 410, through the condenser 202, call-bell 203, and back over the sleeve side of the line through winding 413 of relay 410, passing to ground through protective resistance 247 and battery 248,

part also going to ground through the winding of cut-off relay 209. Although a path from line limb 200 extends to ground through winding 413 of impedance coil 412, its ohmic resistance is such as to prevent an appreciable flow of current through I this path. Upon answering, the calling party at substation M removes his receiver from its hook and thus includes his transmitter 204 in circuit with the line and completes the connection of winding 414 of impedance coil 412 to line limb 201. Under this condition the ohmic resistance of the winding 414 also prevents an appreciable flow of current to ground over the additional path closed to ground upon the removal of the receiver from its hook. The removal of the receiver also allows contacts 420 and 421 of the lamp circuit to come into engagement. With the subscribers lines thus connected, the same circuit conditions exist at substation M as at substation L. It will also be noted that the ringing current will not operate relay 410 because of the opposite magnetizing effect of the windings 412 and 413. The current for the trans- Consequently the operation of relays 219 and 221 has had no efi'ect net 429.

WVith the parties in conversation, and

of the operator is to depress the key425" to set the indicating mechanism into operation. As beforeexplained, the downward movement of the key opens contacts 423 and 424, and contact 423 subsequently engages contact 422. The retarding device 427 causes the contact 424 to slowly return toward its normal position. The delay is timed so that contacts 423 and 424 will first come into engagement at the end ofthe normal conversational period previously assumed as three minutes. This engagement will take place at the time contact 423 is in engagement with contact 422. If it' be assumed that manual switch 433 is in position to close circuit through both relays 434 and 435, then a circuit will be completed which may be traced from the live pole of battery 431 through protective resistance 432, contacts 422, 423 and 424, manual switch 433, and then to ground, through parallel branches, one including the winding of relay 434 and the other thewinding of relay 435. This circuit will be a momentary one, because contact 424 continues upward and forces contact 423 out of engagement with contact 422. The momentary energization of relays 434 and 435, however, applies battery to both sides of the talking circuit, and as a result the drop 400 at substation L and the relay 410 at. substation M are operated. In the case of the drop 400, the circuit over the sleeve side may be traced from the-live pole oi'f battery 431 through the winding 443, closed contact 437, plug and jack sleeve contacts, alternate contact 231, line limb 201, winding 403, switch-hook, 206, winding 409', to ground; and the circuit over the tip side may be traced from the live pole of battery 431 through the winding 442, contact 436, plug and jack tip contacts, alternate con tact 232, line limb 200,-winding 402, andwinding 408 to ground. In the case of the relay 410 at substation M, the circuit over the sleeve side may be traced from the live pole of battery 431 through the winding 445, closed contact 440, plug and jack sleeve contacts, alternate contact 231, line limb 201, winding 413, switch-hook 206, and winding- 414. to ground; and over the tip side the;

circuit may be traced from the live pole of battery 431 through winding 444, closed contact 439, plug and jack tip contacts, alternate contact 232, line limb 200, winding 412, and winding 413 to ground. As a result of the closing of these circuits, the cores 401 and 411 of drop 400 and relay 410,

upon the mag cumulative. flow of current through the traced, through each of the windingsof the cut-oh relays 209. The magnetizing of core This result is not affected by 401- rocks its angular armature about its pivot and-causes the forward end of its upper arm, which extends lengthwise of the 1 core, to disengage the upper and free end of the shutter 405 to allow the latter to drop under the force of gravity to its indieating position. Likewise, the magnetizing of core 411 of relay 410 closes contact 415 which operates relay 417, which I im'me diatel-ylocks up by reason of the locking circuit" through itscontact 418, lamp 419.

and control contacts 420 and 421- to. ground. The closing of the latter circuit lights lamp 419' as an indication to the'party at substation" M that the normal limit of conversation has expired; The dropping of the shutter 405: at substation L serves the same purpose at that station. I V

- Because of the arrangement'of the windings on impedance coils 406, 412, 438 and 441, there is no interference with conversation by reason of their being brought into circuit. They are ofhigh inductance and their windings are difierentially arranged for the voice currents It will thus be seen that with this form of the invention there v is no interference with conversation even conversing parties. Indeed, even if there werea momentary interference wlth the conversation, such interference would of at the time the indications are given to the I itself serve as' an indication to the parties,

just as in the case provided for by the arrangement of Fig. In some cases itnnght be desirable to produce a permanent visual indication at the substations and at the same time an audible indicationcin' the receiver of the-conversing parties If it be desired to operate the indicating mechanism 0 automatically, then the'manualswitch446 is to be closed. so as to com pl'ete the circuit for magnet 429 at the, time j the, plug 213 is inserted into the jack of the called-for line. This will be brought about by the closing of contact448 of sleeve relay 219 at thetime the plug isinserted. The effect of the closing of this circuit will be to: draw the contact424 downward and to respectively, are magnetized because of and the spring 424 of the indicating device will begin its return movement with the re-- sults previously recorded.

At the conclusion of conversation, the res toration of the receiver at substation L will result in lighting the supervisory lamp 222 in the manner explained in connection with the description of Fig.4. The subscriber will then push up the latch 405 of the drop 400 into engagement with the hook on the forward end of the angle armature 404. This will leave all the parts at the substation in normal position. The restoration of the receiver at substation M opens the contacts 420 and 421 and thereby opens the circuit for locking relay 417 and for lighting lamp 419. Relay 417 will then restore to its normal position. The restoration of the receiver will also light supervisory lamp 223, as explained in connection with the description of the system of Fig. 4. The lighting of both supervisory lamps 222 and 228 will indicate to the operator that the connection is to be taken down. This will be done by removing the plugs 212 and 213 and thus all parts will be restored to normal.

In our consideration of the operation of the system of Fig. 6, we have considered substation L as the calling substation and substation M as the-substation called for.

Since'the apparatus at these two stations is prevent interference with the normal opera- I tions of the relays, and the high inductance Will prevent interference with conversation between the operator and the party calling. Upon the operatorscompleting connection to the called-for line, which under our assumption is the line leading to substation L, ringing. current is applied as before and in this case, as before, does not operate the in-- dicating mechanism because of the difi'erential arrangement of the windings with reference to the direction of current flow. During the conversational period the current is supplied in both instances as when the relation of the parties as calling and called-for, was reversed. Likewise, the disconnection signals are operated in the same way.

It will be obvious that the automatic control of the indicating device, which is shown in Fig. 6, may be employed in the control of the contacts of the other indicating devices disclosed in the present application, and that such control may also beemployed '1 are also Wherever the .control circuit for the contact actuating magnet can be extended through a normally open contact, which will be closed when connection is established, and through a normally closed contact, which will be opened when the called-for party responds inanswering his call. The sleeve relay 219 and the tip relay 221 of Fig. 4 are such. relays. The sleeve relay 48 and the. tip relay '49 at the trunk of Fig. such relays. In ordinary practice there are many circuits in which such relays will be found and to which the control circuit may be readily adapted, as will be understood by those skilled in this art. The manual switch 433 of the system of Fig. 6, like the manual switches 97 and 228 of Figs. 1 and 4, respectively may, be placed into position to include only one of the associated branches;

WVhen this is done in the system of Fig. 6, only one party is given an indication at the termination of the normal conversational period. In some instances this arrangement may be preferable to the inclusion of both branches and the notification of both parties. The several retarding devices, 96, 227, 308, 809, 426 and 427, are shown as dashpots in which the piston is provided with an aperture having a suitable flap valve 500, but it Will be understood that any other suitable timing or retarding device may be employed for this purpose. Many other forms will suggest themselves to persons skilled in the art.

In carrying out our invention, it will be apparent that other alterations and modifications might be made without departing from the spirit and scope of the invention. Such alterations and modifications we desire to cover by the terms of the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States 1s:

1. A telephone system comprising telephone lines, a plurality of uniting means for uniting said lines into independent conversatio'nal circuits, an operators position having corresponding parts of the different uniting means arranged in order before the operator, an electrically actuated indicating device associated with each uniting means. manually operable contacts for each uniting means positioned at the operators position in association with the other said parts helonging to that particular uniting means and operative to vary a circuit to start the corresponding indicating device, and delay means for retarding the operation of said contacts.

2. A telephone system comprising telephone lines from substations to a central station, conductors at the central station for said local circuit, contacts in said local oil"- cuit operative in response to applied pressure' to vary said local circuit by a relatively quick movement in onedirection, and delay means for giving said contacts a relatively slow movement in the opposite direction.

3. A telephone system comprising telephone lines from substations to central station, conductors at the central station for uniting said lines, an indicator at one or said stations, connections at said stations operative to close a control circuit forsaid indicator over portions of the associated line and uniting conductor, other c0nnections operative to provide a local control circuit for said indicator local toone of said stations, a source of direct current in said local circuit, manually operable contacts in said local circuit operative under manual pressure to move quickly to vary said circuit, and delay means for causing a-nrelatively slow return of said contacts to normal.

4. A telephone system comprising telephone lines, means for uniting said lines into a conversational circuit, an operators signal, an operators key for displaying said signal, retarding means associated with said key and operative to delay the display of said signal until adefinite time interval following the initial actuation of said key, and means controlled over a telephone'line to eiiace said signal.

5. A telephone system comprising tele phone lines, means for uniting said lines into a conversational circuit, an electric lam-p before an operator, a local circuit for said lamp, an operators key for closing said circuit operative to close the same only after a definite time interval measured from the instant of initially actuating said key, and an'electromagnetically actuated switch for opening said local circuit to extinguish said lamp in response to a control exercised over an associated telephone line.

6. A telephone system comprising atelephone line extending from a substation to a central station, a conductor at the central station for connecting to said line, an indicator at the central station, connections at said stations operative to close a control circuit for said indicator over portions of the associated line and connecting conductor, other connections at the central station operative to provide a control circuit local to the central station, a source of current in quick movement in onedi-rection, and delay means for giving said contacts a relatively slow movement in the opposite direction.

7. A telephone system comprising a telephone line extending between two stations, a conductor atone of said stations for connecting to said line, an indicator at one of said stations, connections at said stations operative to close a control circuit for said indicator over portions of the associated. line and connecting conductor,other connections at one of said stations operative to provide a circuit local to that station, a source of current in said local circuit, contacts in said local circuit operative in response to applied pre'ssuretovary said'local' circuit-by a relatively quick movementin one direction, and delay meansfo'r giving said contacts a rel-a tively slow movement in the opposite direction. i

8-: A- telephone system comprising telephone linesextending to a central station, conductors for use in connecting said lines into conversational circuits, indicator at said station, a control circuit for said indicator local to said station, means for varying said local circuit in response to the connection of one of said conductors to one of said, lines, means whereby a subscriber may sub seqnently exercise a control over his line to again vary said local circuit, and means whereby a retarded action of said indicator may be brought about upon the establish'- ment; or suitable conditions in said local circuit;

9-; A telephone system comprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, an indicator at said station, a control circuit for said-indicator local to said station, means for vary- I ing said local circuit upon connection of one ofsaid conductors to one of said lines, means whereby a subscriber may subsequently exercise a control over his line to again vary said local circuit, and contacts readily movable in one direction and retarded in their movement in the opposite direction, connected' in said local circuit and operative upon the establishment of suitable conditions in said local circuit to delay the indicating action of said indicator until the lapse of a definite time interval.

10. A telephone system comprising telephone lines extending to a central station; conductors for use in connecting said lines intoconversational circuits, normally quiestion of such single indication to return to and remain in its normal quiescent condition until again started, and means for controlling said indicating means over a connected line and conductor.

11. A telephone system comprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, normally quiescent indicating means at the central station operative to produce'only one indication for each operation and then only after a definite time interval, and then after the production of such single indication to return to and remain in its normal quiescent condition until again started, and means for controlling said indicating means over a connected line andconductor.

12. A telephone system comprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, an indicator, a circuit for said indicator, means for varying said circuit in response to the connection of one of said conductors to one of said lines, means beyond operator control for controlling said circuit, and retarded contacts for controlling said circuit.

18. A telephone system comprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, an electrically actuated indicator, an operator-controlled relay having contacts controlling the indicator circuit, a relay controlled over a con ne'cted line and conductor and having contacts controlling the indicator circuit, and a key having retarded contacts for use in cooperation with said relay contacts in bringing about a retarded indication by said indicator.

1A. A telephone system comprising telephone lines extending ,to a central station, conductors for use in connecting said lines into conversational circuits, electrically actuated indicating means, connections for establishing a circuit for said means, electrically actuated means at the central station operative to vary certain of said connections in response to the connection of one of said conductors to a telephone line, electrically actuated means controlled over a connected line and conductor to vary other of said connections, and retarded contacts among said connections for bringing about a retarded indication by said indicator.

15. A telephone system comprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, means for dis playing a signal only after a definite time interval following each starting and thereupon maintaining the same displayed While the parts of said means are otherwise at normal, means under operator control for starting saiddisplaying means, and means beyond operator control for subsequently effacing said signal.

16. A telephone system comprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, a signal lamp, retarded means for lighting said lamp after the lapse of a definite period of time after starting and for thereupon maintaining the same lighted, means under operator control for starting said retarded lighting means, and means beyond operator control for subsequently extinguishing said lamp.

17. A telephone system comprising telephone lines, conductors for use in connecting said lines into conversational circuits, an indicator, a circuit including said indicator, two relays having contacts in said circuit and operative to make and break said circuit at different points, mean cooperating with said lines andconductors to provide control of said relays by both a subscriber and an operator, and operator-controlled retarding means for delaying the establishment of the indicating condition of said circuit.

18. A telephone system comprising telephone lines, conductors for use in connecting said lines into conversational circuits, an indicator, a control circuit for said indicator, means for varying said control circuit in response to the connection of one of said conductors to one of said lines, and operator-controlled means whereby a retarded action of said indicator may be brought about upon the establishment of a suitable condition in said control circuit.

19. A telephone system comprising telephone lines, conductors for use in connecting said lines into conversational circuits, an indicator, a control circuit for said indicator, means for varying said control circuit in response to vthe connection of one of said conductors to one of said lines, and contacts readily movable in one direction and retarded in their movement in the opposite direction, connected in said control circuit and operative upon a suitable condition in said control circuit to delay the indicating action of said indicator until the lapse of a definite time interval.

20. A telephone system comprising tele phone lines, conductors for use in connecting said lines into conversational circuits, an indicator, solely operator-controlled means for-starting said indicator, means beyond operator control for exercising a subsequent control over said indicator by a circuit including'a connected line and conductor, and

means whereby a retarded action of said indicator may be brought about.

21. A telephone system comprising subscribers telephone lines, conductors for use in connecting said lines into conversational circuits, an indicator, solely operator-controlled means for starting said indicator,

means under subscriber control for exercising a subsequent control over said indicator, and means whereby a retarded action of said indicator may be brought about.

22. A telephone system comprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, an indicator, electrical connections for said indicator local to said station, solely operator-controlled means for varying said connections to start said indicator, means beyond operator control for subsequently varying said electrical connections to stop said indicator, and

means whereby a retarded action of said indicator may be brought about.

23. A telephone system comprising subscribers telephone lines extending from substations to a central station, conductors for use in connecting said lines into conversayond operator control for exercising a subsequent control over said indicator by a circuit including a connecting line and conductor, and contacts readily movable in one direction and retarded in their movement in the opposite direction, connected in circuit with said indicator and operative upon the establishment of suitable conditions to delay the indicating action of said indicator until the lapse of a definite time interval. 1 i

25. A telephone system comprising subscribers telephone lines extending from sub-.

stations to a central station, conductorsfor use in connecting said lines into conversa tional circuits, an indicator at said central station, solely operator-controlled means for starting said indicator means under subscriber control for exercising a subsequent control over said indicator, and contacts readily movable in one direction and retarded in their movement in the opposite direction, connected in circuit with said indicator and operative upon the establishment of suitable conditions to delay the indicating action of said indicator until the lapse of a definite time interval.

26. A telephone system comprising telephone lines extending to. a central station, conductors for use in connecting said lines into conversational circuits, an indicator at said station, a control circuit for said indicator local to said station, solely operatorcontrolled means for varying said local circuit to start said indicator, means beyond operator control for subsequently varying said local circuit, and contacts readily movable in one direction and retarded in their movement in the opposite direction, connected in said local circuit and operative upon the establishment of suitable conditions in said local circuit to delay the indicating action of said indicator until the lapse of a definite time interval.

27. A telephone systemcomprising telephone lines extending to a central station, conductors for use in connecting said lines into conversational circuits, an indicatorat said station, a control circuit for said indicator local to said station, solely operatorcontrolled means for varying said local circuit to start said indicator, means whereby the subscriber may subsequently'exercise a control over his line to again vary said local circuit, and contacts readily'movable in one direction and retarded in their movement in Witnesses:

R. L. STERLING, E. G. MATTINCE.

In Witness whereof, I, THOMAS H. FERGU- SON, have hereunto subscribed my name this 23rd day of January, A. D. 1914.

THOMAS H. FERGUSON.

Witnesses: p

HENRY S. SHEDD, IQE. LARSEN.

Copies of this patent may be obtained for five cents each, by addressing the (Commissioner of Patents,

Washington, D. G.

EDWARD H. MARTIN.

' the opposite direction, connected'in said 10-

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