US2382164A

US2382164A - Detergent briquette

Info

Publication number: US2382164A
Authority: US
Publication date: 1945-08-14
Anticipated expiration: 1962-08-14

Description

Patented Aug. 14, 1945 na'raaoan'r naroua'r'ra James Douglas MacMahon, Niagara Falls, N. Y., assignor to The Mathicson Alkali Works, Inc., New York, N. Y., a corporation of Virginia No Drawing. Application January 31, 1942, Serial No. 529,128

6 Claims.

This invention relates to an improved briquetted detergent compound. The briquette of my present invention is unique in its combination of detergent characteristics and other physical and chemical properties which make it highly satisfactory for use in modern mechanical washing operations.

Modern mechanical methods and apparatus for washing dishes, milk cans and the like, particularly where the operation is continuous or prolonged, have presented the serious problem of maintaining an alkali concentration in the wash tanks between desirable and restricted limits. Commercial experience has shown that this may be accomplished in a dependable and virtually automatic manned by dissolving alkaline briquettes in suitable auxiliary equipment and dispensing the resulting solution into the wash tanks at a predetermined rate. A very considerable amount of research has been carried out in view of developing detergents having chemical and physical characteristics satisfactory for this purpose.

The problem presented involves not merely the production of a material or mixtures of materials having the desired detergent characteristics but also the development of a product which, in addition' to meeting that requirement, can be economically produced in the desired physical form possessing other essential physical characteristics.

For instance, it is desirable that the detergent be in briquetted form; that the briquettes be sufficiently hard and strong to withstand ordinary handling; be chemically and physically stable and non-deliquescent so as to withstand storage and the necessary handling and of such structure as will not disintegrate under the conditions of use.

Inasmuch as the control of the rate at which the alkali is dispensed into the washing operation largely depends upon the dissolving rate of the briquette, it is desirable that the briquette not only have a satisfactory degree of uniformity in its composition but also that it have a uniform solubility rate.

It is, of course, also essential that the composition of the cleansing solution be such as to avoid harmfully affecting the material being washed either by attacking the material or by forming deposits or coatings thereon. It is further essential that the composition of the detergent be such as to avoid deleteriously affecting the .parts of the mechanical washer and the deposition of scale'in the various chambers thereof.

It has been proposed to produce detergent briquettes for such use by fusing the detergent or detergent mixture and casting the-fused material by drawing it 01! into molds to cool. For example, briquettes have been produced by fusing mixtures of trisodium phosphate and soda ash. However, the relatively high temperatures required to fuse the detergent or detergent mixtures have been a decided handicap in the production of satisfactory detergent briquettes, as many substances, the presence of which is highly desirable in detergent mixtures, are driven off or decomposed at temperatures below their fusion point or at temperatures necessary for fusing other desirable constituents.

This temperature requirement has not permitted the incorporation in detergent mixtures so produced of many very effective water conditioners and surface active agents such as synthetic detergent and wetting agents. Consequently, the use of such fused detergent briquettes has not been wholly satisfactory. For instance, particularly under adverse water conditions, their use has resulted in the precipitation of natural hardness of the water supply and the tendency to form scale on the inner surfaces of the mechanical washers with which the detergent is used. Rapidity of this scale formation de- Also, the addition of surface active agents has been found further to enhance the cleansing action and to afford improved rinsing. However, for the reasons stated above, the incorporation of these materials in fused anhydrous detergent briquettes has been impractical.

Detergents have heretofore been produced in block form by crystallization or solidification of the detergent or detergent mixtures from aqueous solutions; for instance, by the evaporation of waterthe'refrom or by causing a chemical or physical union of the water or a proportion thereof with the detergent. The resulting blocks produced prior to my invention have fallen short of the requirements essential to their satisfactory commercial use in mechanical washing operations.

The detergent briquett of my present invention may be formed without resort to high tennperatures and its constituents and proportions thereof may be varied ov'era considerable range to meet the requirements of the particular washing operations in which they are to be used. Further, the physical limitations and deficiencies common to previous detergent briquettes are overcome. My improved briquettes consist of a dense crystalline aggregate of relatively uniform composition. They are hard and strong and physically stable, being capable of withstanding the conditions of shipment and storage essential to ultimate commercial us without material deterioration, disintegration or deliquescence. They do not disintegrate under normal conditions of use and have a uniform solubility rate. Further, ther is no objectionable chemical change in the composition of the briquette. Also, since they can be produced without resort to high temperatures, .various desirable addition agents unstable at higher temperatureg may be incorporated therein to meet special water conditions or detergent requirements. Accordingly, objectionable precipitations of natural hardness of the water used may be inhibited or greatly reduced and the detergent action of the resulting washing solution materially improved. Further. the congealing and hardening time of my briquettes during molding is suiliciently rapid to permit their economical commercial production.-

. The detergent mixtures of which my improved briquettes are composed are prepared by mixing with sodium silicate in the manner and proportions hereinafter fully described various materials previously known to have detergent or watar-conditioning properties. My invention is based on my discovery that various combinations of such materials. in proportions hereinafter described, may be compounded with the sodium silicate to form briquettes having the abovenoted desirable characteristics and without resort to obiectionably high temperatures.

The sodium silicate ingredient of my improved briquette is one in which the NasOtSiOz ratio is less than unity, that is one having an alkalinity lower than that of the metasilicate. Satisfactory briquettes may be prepared in accordance with my invention using proportions of the sodium silicate within the range of about 1% to about 20%. I

The ingredients which may be combined with the silicate, in accordance with my invention, comprise trisodium phosphate, sodium carbonate. various water conditioners such as a sodium polyphosphate, for instance tetrasodium pyrophosphate, sodium hexametaphosphate, sodium tetraphosphate and various synthetic detergent or wetting agents hereinafter more fully identified.

The permissible range of proportions of these ingredients in producnig briquettes having satisfactory molding characteristics and physical structure appears to depend on the low alkalinity of the sodluni silicate ingredient. Where a sodium silicate having an alkalinity as high as that of the metasilicate or higher is used, 1. e, one

2,882,164 where the. NaaOzSiO: ratio is unity or greater,

satisfactory molding and structural characteristics are not ordinarily obtained if the proportion of trisodium phosphate exceeds about 15% by weight. By adding controlled proportions of sodiumhexametaphosphate or sodium tetraphosphate, this maximum permissible proportion of. trisodium phosphate may be raised to about 35% by weight. Further, usinga sodium silicate of alkalinity equal to that of metasilicate or greater in briquettes of th general type herein described, the trisodium phosphate ingredient may not be reduced below about 1% byweight without experiencing diiiiculties.

In the briquettes of my present invention,

wherein a sodium silicate having an NaaOZSiOz ratio less than 1 is used, the trisodium phosphate may be entirely omitted, provided a considerable proportion of sodium carbonate is used, or it may b added in proportions equal to approximately half the formula weight, for instance about 50% to 60% of anhydrous trisodium phosphate may be added, either with or without the addition of the pyrophosphate, the metaphosphate or the tetraphosphate, without destroying the desirable physical structure of the briquettes or rendering the molding time impracticable. 7

Similarly, where the alkalinity of the sodium silicate ingredient is equal to that of the metasilicate or higher sodium carbonate appears to be an essential ingredient of briquettes of this character. However, in the briquette of my present invention, sodium carbonate may be entirely omitted, provided a considerable proportion of trisodium phosphate is used, or sodium carbonate may be added in proportions equal to approximately half the formula weight.

In addition to the sodium silicate of the character described, other essential ingredients of the briquette of my present invention'are water and either trisodium phosphate or soda ash or both.

The amount of water present in the detergent composition is of major importance with respect to molding time and mechanical structure 'of the resultant briquette and also its detergent capacity. It is essential that suiiiclent water be present during the processing to produce under processing conditions a mass sufllclently fluid to permit satisfactory mixing and pouring into the molds and have satisfactory molding characteristics. However, the addition of an excess of water is generally to be avoided since the processing normally does not involve conditions under which excess water would be eliminated.

I have found the permissible range of proportions of water in my briquetted product to be from about 30% to about 40% by weight. As above noted, it is necessary that the product contain suflicient water to permit satisfactory pouring and molding but an increased amount of water in the product results in a corresponding reduction in the alkali content of the briquette. The proportion of water present also has a distinct eil'ect upon the physical characteristics of the briquette. Proportions of water in the prodnot up to about 40% by weight do not materially increase the congealing time or detrimentally affeet the physical structure of the briquette. However, a proportion of water in excess of about 40% has been found to increase the molding time to impracticabllity and to affect adversely uniiormity of structure of the resulting briquette. when the water content much exceeds this upper limit there is a tendency toward segregation during the congealing period.

The optimum amount of water present in the iinished product appears to depend to a considerable extent upon the proportion of other ingredients added. Usually, more satisfactory results are obtained where the proportion of water is not much in excess of that required to give sumsatisfactory molding characteristics and physical structure, in addition to having the other physical and chemical properties previously related, may be prepared to meet practically any detergent condition in which the use of detergents in briquetted form is practical.

I have found the permissible proportion of anhydrous trisodium phosphate which may be added in the compounding of the briquettes of my present invention is mainly dependent upon the NMOZSiO: ratio of the sodium silicate constituent. Where the Na20:SiOa ratio of the sodium silicate ingredient in briquettes of this general type approximates unity, the proportion of anhydrous trisodium phosphate which may be added without impairing the structure of the briquette cannot greatly exceed by weight. I have discovered, however, that, as this ratio is reduced, the proportion of trisodium phosphate which may be added with advantage may be increased up to about half of the formula weight. For example, where the NasOzSiO: ratio of the silicate constituent is reduced to about 1:2.5, the trisodium phosphate constituent may be increased to about Where this ratio is further reduced to about 1:3.22, the proportion of trisodiumphosphate added may be increased to approximately 35% and, by reducing this ratio to 1:3.86, the proportion of trisodium phosphate added may be increased to approximately 60%.

In the preparation of my improved briquettes, the sodium silicate constituent is most conveniently and economically added in the form of water glass. I have obtained excellent results in many instances by using a sodium silicate in the form of water glass of 41 B. gravity and consisting of 8.9% NazO, 28.7% SiOz and 62.4% water. In this form the ratio of Na2O:SiOz is 1:3.22. Where a silicate of higher alkalinity is desired, caustic soda may be added in an amount appropriate to increase this ratio to the desired value which in any event should be less than unity. Where it is required that the Na2O:SiOz ratio of the sodium silicate constituent be less than 1:21.22, 1 have with advantage added the sodium silicate constituent in the form of water glass of 35.5 B. gravity consisting of 6.4% Na2O, 24.7% SiOz and 86.9% water, the NazOtSiOz ratio thereof being 1:3,.86. This ratio may, of course, be adjusted upwardly, if desired, by the addition of appropriate proportions of caustic soda.

Since the percentage of water in water glasses increases materially as the NazozsiOz ratio decreases, the proportion of the extremely low ratio water glass which may be added, without introducing into the mixture excessive amounts of water, is limited. Therefore, it may not always be permissible to use such amounts of low ratio water glass as would be necessary to increase the anhydrous sodium silicate proportion to the upper limit of the ranse without encountering operating dimculties in removing the excess water from the detergent mixture prior to molding.

Sodium silicates in solid form, which are sufiiciently soluble under compounding conditions and which have an NazOzBiO: ratio less than unity, may be substituted in whole or in part for water glass providing appropriate allowances be made for diiferences in composition.

Where caustic soda is used to increase the alkalinlty of the water glass, it may be supplied in solid form such as the usual commercial grade of about 76% NazO. However, other forms of caustic, such as the commonly available 60% solution, may be substituted provided appropriate allowances be made for the difl'erences in composition.

The trisodium phosphate may be introduced in the form of the ordinary commercial dodecahydrate, generally represented by the formula NaaP04.12H2O. Theoretically this material contains 56.8% water. However, repeated analyses indicate that the water content of the trisodium phosphate dodecahydrate which I have used in the development of my improved briquette is approximately 53%. Consequently, the proportions of such material given herein are based upon the latter value of water content. Trisodium phosphate of lower water content than the dodecahydrate may be used provided appropriate compensation be made for the proportion of water contained therein. If an excessive water content of the batch is to be avoided, a trisodium phosphate having a water content lower than the dodecahydrate should be used when the proportion of anhydrous trisodium phosphate to be added is to exceed approximately 30% by weight.

Materials which react under the process conditions to form trisodium phosphate, for instance disodium phosphate and caustic soda, may be substituted for an equivalent proportion of .trisodium phosphate, appropriate allowance being made for the water content of such reacting materials and water produced by the reaction.

The sodium carbonate may conveniently be added asanhydrous soda ash. However, it may be supplied in the form of hydrates such as mono or deca hydrates, appropriate allowances being made for differences in composition. Similarly, the tetrasodium pyrophosphate, sodium hexametaphosphate or sodium tetraphosphate may be supplied in the usual anhydrous form and proportions thereof appearing herein have reference to such materials.

If desired, a water conditioner such as previously mentioned sodium poly-phosphates may be added to meet special water requirements. I have with advantage added such materials in proportions up to about 15% by weigh-t. Such proportions of tetrasodium pyrophosphate, sodium hexametaphosphate or sodium 'tetraphosphate have been found usually to be sufiicient for most water conditions. However, an amount'in excess of 15% may be added if desired without impairing the physical structure of the resultant briquette. Where the addition of a water conditioner is required, a minimum proportion of about 2% or 3% is usually desirable. However, in accordance with this invention, any effective minimum may be used or, if desired, such material may be entirely omitted. 1

Aside from their water-conditioning characteristics, I have foundjthe addition of these phosphates to the detergent mixture to influence favorably the molding time and physical structure of the resultant briquettes. The extent of their influence is not identical and varies somewhat wlth the proportions of other ingredients used. For example, I have found the addition of either sodium tetraphosphate or sodium hexametapnosphate favorably to influence the molding and structural characteristics of the mixture, particularly when used in proportions approaching 15% by weight, where the higher permissible proportions of trlsodium phosphate are added and especially where the alkalinity of the sodium silicate ingredient approaches that of the metasilicate. Also, where no trisodium phosphate but a large proportion of soda ash is added, the addition of tetrasodium pyrophosphate has been found to improve both the molding time and the structure of the briquettes. Under such conditions, the effect of the pyrophosphate is more pronounced than that of the sodium tetraphosphate and is still greater than that of the sodium hexametaphosphate. When about 5% of anhydrous trisodium phosphate is added, the effect of the addition of the pyrophosphate, with respect to molding and structural characteristics, is less pronounced. Further, when the NazOISiOz ratio of the sodium silicate ingredient approaches unity, the proportion thereof may be extended somewhat above 20%, for example to approximately 25%, by the addition of either the pyro, the meta or the tetra phosphates above mentioned in proportions in the upper portion of the range for those ingredients. The sodium tetraphosphate appears to be more efiective than the tetrasodium pyrophosphate, particularly with respect to molding time. The metaphosphate is less efiective under these conditions than either the py'rophosphate or the tetraphosphate and excessive amounts of the metaphosphate are apt to cause unsatisfactory kettle conditions due to a tendency to form lumps. Where the alkalinity of the silicate content approaches the upper limit of the range and the proportion of trisodium phosphate approaches the upper permissible limit for that particular alkalinity, proportions of the 'trisodium phosphate, caustic soda and additional water, or such of these materials as are to be used, are placed in the kettle and heated with The fluid mass is held at this temperature until the mass clarifies, advantageously until maximum .clarity is obtained. This usually requires from tures which would result in the material loss of water. The metaphosphate or tetraphosphate is advantageously added and thoroughly mixed in the mass in the kettle just prior to pouring. Care should be exercised in the incorporation of these materials with the hot mixture in the kettle to avoid a possible violent reaction whenthese maerials are added, particularly when added in large amounts. The temperature should be at a minimum for adequate pouring fluidity. These precautions need not be taken when the pyrophosphate is used. The latter may be added advantageously prior to the addition of the soda ash, particularly if the pyrophosphate is in a slowly soluble form.

The mixture is finally drawn off into suitable molds and allowed to congeal until the briquette has developed suficient mechanical strength to permit its removal from the mold. The necessary molding time will generally vary from about 1 hour to several hours, depending upon the composition of the mixture. Where a sodium silicate other than water glass is used, it should be placed in the kettle at that stage of the operation where the water glass would have been introduced.

On cooling, detergent compositions of this type seem to expand somewhat and this, combined with the tendency to adhere to metal surfaces of the molds, has previously presented considerable dimculty in the molding of detergent materials. I have found that, by using flexible d5 briquette molds such as molds made of rubber or pyrophosphate may with advantage be as high constant agitation until the mass is fluid. .The

similar materials, these dificultiesare eliminated.

Where it is desirable to incorporate in the briquettes a so-called surface active agent, such material may he introduced into the mixture just prior to withdrawal from the kettle. However, where such addition agent is ln-solid form and g has a relatively slow rate of solubility, I prefer to add it prior to the addition of the soda ash. Various surface active agents capable of withstanding the necessary pouring temperatures in an alkaline environment may be so incorporated in my briquettes to meet special conditions encountered in specific detergent operations for which the briquettes are intended; for example, a product consisting principally of sodium lauryl sulfate, marketed under the trad name Orvus, or one consisting principally of soodium dodecyl benzene sulfonate, marketed under the tradename Naccono each of which I have used to advantage.

The following formulae are presented as specific examples of proportions of the several ingredients which have been used with advantage in the preparation of my improved briquettes where water-conditioning agents but no surface active agents are used. It will be understood, however, that my invention is not limited to a product prepared from the particular formula shown. In each instance the proportions are by weight.

asaanos Water ass. 5 5 5 2 55 15 1lzivrophosphate. 2. 6 i 15 7 etaphosphsta. Tetra hosphate is Add water 34.8

ent was one in which the Na:O:BiO: ratio was 1:3.86. In Examples 2 to 6, inclusive, the ratio of' the water glass was 1:3.22

In the following tabulation, the proportion of the trisodium phosphate and the water glass constituents have been reduced to an anhydrous basis with the water added as trisodium phosphate hy- Examples 1 and 4 illustrate, respectively. about the maximum proportions of anhydrous trisodium phosphate and soda ash which may be added.

Where the presence of a surface'active agent, such as the previously mentioned synthetic detergents and wetting agents, is desirable, a. maximum of about 5% by weight has been found sufficient for most purposes where a detergent in briquetted form can advantageously be adopted. Usually smaller proportions are sufiicient. Proportions even as small as 0.1% have a perceptible effect upon the solubility rate of the resultant briquette and the wetting characteristics of the washing solution.

Where these surface active agents are used and the tetrasodium pyrophosphate omitted, special precautions must be observed if briquettes having the most desirable physical structure and molding characteristics are to be obtained. Generally, it may be stated that, where these surface active agents are to be incorporated in the briquette, best results are obtained when trisodium phosphate is also present in appreciable proportions. Where the anhydrous trisodium phosphate content is as high, for instance, as satisfactory results have been obtained using either of the water glasses heretofore mentioned with proportions of surface active agents ranging up to about 5%.

Generally, where trisodium phosphate is present in considerable proportions, more uniform results are obtained where the NasOtSiO: ratio of silicate constituent is lower than 123.22. In such cases, more advantageous results are obtained where this ratio approximates 1:3.86. Where the proportion of trisodium phosphate added approaches the upper limit of the range, it is desirable that the proportion of the surface active agent not exceed about 1%.

The following formulae are presented as speciflc illustrations of proportions of the several ingredients which have been used with advantage in the preparation of my improved briquette where a surface active agent but no water conditioner was added. It will be understood, however, that my invention is not limited to a Product prepared from the particular formula shown. In each instance the proportions are by weight.

Batch No.

'Irisodium phosphate 32 32 52. 8 16 16 Soda ash 43.9 39.4 N 6 50.3 45.8

In each of the Batches 7 to 11, inclusive, the trisodium phosphate added was a dodecahydrate. In Batches 7, 8 and 9, the Na:0:SiOz ratio of the water glass was 1:3.86 and, in Batches 10 and 11, a water glass having a ratio of 1:322 was used. The surface active agent used in Batches 7, 8 and 9 was that previously identified herein as Orvus and, in Batches 10 and 11, the surface active agent was that previously identified as Nacconol."

In the following tabulation, the proportion of the trisodium phosphate and the water glass constituents have been reduced to an anhydrous basis with the water added as trisodium phosphate hydrate and as water glass included in the approximate percentage of total water.

Batch No.

'Irisodium Phosphate l5 15 24. 8 7. 5 7. 5 Sodaash 43.9 39.4 26.6 50.3 45.8 Sodium silicate .5. 6 5. 6 5. 5 5. 6 5. 6 Surface active agent 0. 5 0. 5 2. 5 0.5 5.0 Total water (approx.) 35 35 40. 5 36 36 and avoiding temperatures at which there would V be any material loss of water by vaporization.

The composition of my briquetted product so' prepared from the ingredient of the preceding specific examples, exception those where sodium tetraphosphate or sodium metaphosphate was added, was substantially as shown both with respect to the percentages of solid ingredients and the percentage of total water.

However, in the compounding of my briquettes, I have observed a slight temperature increase when sodium tetraphosphate or sodium metaphosphate is added to the mixture which suggests the possibility of chemical reaction. I am at present unable definitely to state the nature or extent of such chemical reaction, if in fact it does occur.

It is possible that the tetraphosphate or the metaphosphate reacts with one or more of the other ingredients, but I am at present unable by chemical analysis of the final product to-determine with certainty the nature or extent of such reaction. 7

Excepting that the various ingredients must be compounded at a temperature at which the mass is sufllciently fluid for pouring and molding, my invention is not dependent upon the particular process used. Preferably, the compounding temperature should not much exceed that at which fluidity necessary for molding is obtained. If there are excessiv losses of water by vaporization during the process, such loss of water may be replaced just prior to the drawing oil of the batch into molds. Also, if the total amount of water introduced into the batch should exceed 30 %-40% by weight, the excessive water may be removed by vaporization.

This application is in part a continuation of my co-pendlng application Serial No. 389,619, filed April 21, 1941.

I claim:

1. A detergent briquette physically stable, hard, strong, and non-diliquescent consisting of a dense, crystalline aggregate consisting essentially of the following ingredients in proportions by weight within the respective indicated ranges: sodium silicate of which-the ratio of NazOISiOz is less than 1:1 about l%20%, total water about 30%- 40%, and at least one detergent of the group consisting of sodium carbonate and trisodium phosphate aggregating from about one-fourth to about one-half the total formula weight.

2. A detergent briquette physically stable, hard, strong, and non-diliquescent consisting of a dense, crystalline aggregate consisting essentially of the following ingredients in proportions by weight within the respective indicated ranges: sodium silicate of which the ratio of NazOzsiOz is less than 1:1 about 1% to 20%, total water about 30%-40%, at least one detergent of the group consisting of sodium carbonate and trisodium phosphate aggregating from about one-fourth to about one-half the total formula weight, and about 0.1 to about of an alkali-stable nonsaponaceous, synthetic, organic surface active agent.

3. A detergent briquette physically stable, hard,

strong, and non deliquescent consisting oi a crystalline aggregate consisting essentially of the following ingredients in proportions .by weight within the respective indicated ranges: sodium silicate, of which the ratio of Nazozsioz is less than 1:1 about 1% to 20%, total water about 30% to at least one detergent of the group consisting of sodium carbonate and trisodium phosphate aggregating from about one-fourth to about one-half the total formula weight, and about 3% to 25% of tetrasodium pyrophosphate.

5. A detergent briquette physically stable, hard,

strong, and non-deliquescent consisting of a dense, crystalline aggregate consisting essentially of the following ingredients in proportions by weight within the respective indicated ranges: sodium silicate of which the ratio of NazOzsiOz is less than 1:1 about 1% to 20%, total water about 30% to 40%, at least one detergent of the group consisting of sodium carbonate and trisodium phosphate aggregating from about onefourth to about one-half of the total formula weight, and about 3% to 20% of a sodium polyphosphate.

6. A detergent briquette physically stable, hard, strong, and non-deliquescent consisting of a dense, crystalline aggregate consisting essentially of the following ingredients in proportions by weight within the respective indicated ranges: sodium silicate of which the ratio of NazOzSiOz is less than 1:1 about 1% to 20%, total water about 30% to 40%. at least one detergent of the group consisting of sodium carbonate and trisodium phosphate aggregating from about one-fourth to about onehalf of the total formula weight, about 0.1 to about 5% of an alkali-stable, non-saponaceous, synthetic, organic surface-active agent, and about 3% to 20% of a sodium polyphosphate.

\ JAMES DOUGLAS MACMAHON.

CERTIFICATE OF comcwxon. Intent No. 2,582,131,. August 11;, 191

JAMES noucms HacMAHON.

It is hereby certified that error appears in the printed specification above numbered patent requiring correction as .follo'ive: Page 1, first column, line 16, for "manned" read --manner-'-; line 33, for "briquettod" Mia-ad -;:r1quette--; page 2, first column, line 70, for "producnig" read ---pIMFiGing-; page 5, second column, line 1414., in the table, third column opposite the words "Surfaceecfdve agent for "(5.5" read -5.0-; for "eiception" read ---excepting--; page 6, first column, lines V i; i and second column, line 12, for "non-diiiquescent" read -nonhelm-descent; and that the said Letters Patent should be readwith this ccrrec ti on herein that the same may confom to the record of the case in ezzt fif'fice.

.. and sealed this 18th day of December, A. D. 1914.5.

Leslie Frazer