US2239692A - Continuous process of treating oils - Google Patents

Description

April 29, 1941. 0, v 2,239,692

cou'n'nuousraocass OF TREATING OILS Filed 061. 21, 1938 4 20 21 a? a4 3 10 24 i as 28 a! a0 14 1 OIL * Patented Apr. 29, 1941 UNITED] STATE 5 PATENT! OFFICE CONTINUOUS PROCESS OF TREATING Q1118 Otho M. Behr, Redondo Beach, Oali1., Oil Products Company,

a corporation of Delaware Vegetable Angeles, Cali1' minor to Inc'., Los

- Application October 21, 1938, Serial No. 236,228

13 Claims.

This invention pertains to methods of treating fatty oils such as animal vegetable and marine oils, in a continuous manner to the end that mediate oil is unsuited for use either as'anedible oil or as a drying oil. The present invention is particularly directed toward the treatment of distinct liquid products be produced therefrom.

The invention also relates to means and devices whereby the process may be carried out most effectively.

Substantially all oils are composed in major proportions of compounds of fatty acids with glycerol, such compounds being known as glycerides". Mono-, diand tri-glycerides are well known. Since the fatty acids combined with the glycerol will vary greatly in formula and molecular weight, the glycerides also vary materially in molecular weight, molecular size and other properties. For example, the refractive index of an oil increases with the mean molecular weight of the glycerides contained therein.

The fatty acids combined with the glycerol may be either saturated or unsaturated and most oils contain both saturated and unsaturated constituents. The iodine value normally assigned'to oils containing a mixture of both saturated and unsaturated glycerides whereby two or more separate and distinct liquid products may be produced, each of these products having properties which render it eminently suited for use in a sepoils is a measure of unsaturation and is closely associated with the ability of the'oil to absorb oxygen and this in turn is indicative of the drying' power of the oil. I term but most vegetable, marine and other oils are classified as either drying or non-drying. It may be generally stated, however, that the drying oils are those which contain a very large proportion of the more unsaturated constituents or glycerides whereas non-drying oils contain less Drying power" is a relative highly unsaturated and saturated compounds in major proportion. Linseed oil is an example of' a drying 011 whereas cottonseed oil is a substantially non-drying oil. Oils containing saturated and less highly unsaturated constituents are usually employed and referred to as edible oils,

the more unsaturated oils being generally considered as drying or non-edible.

Attention is here called to the fact that glycerid'esof oleic acid (which contains but a single double bond) occur in non-drying oils and such glycerides are embraced by the term "less highly unsaturated constituents" or non-drying constituents. Glycerldes of linoleic acid, etc., are the more highly unsaturated constituents of dryingoii type but upon polymerization some of these may lose their double bonds in part or even altogether.

Most oils are a mixture of glycerides and such mixture contains both saturated and unsaturated compounds. The resulting oil, therefore, partalres of the properties of both drying and nondrying 011s and in'many instances such an interhigh molecular weight,

ment of partly polymerized oils.

oil as, for example,

arate and distinct field.

Polymerization, condensation or heat-bodying of an oil containing a mixture of both saturated and unsaturated constituents results in molecular unification of the highly unsaturated compounds, thereby producing compounds of larger molecular size and of heavier molecular weight. The saturated or non-drying glycerides do not readily increase in molecular size during polymerization. The present invention contemplates the treat- By partial polymerization," reference is made to a heat treatment of an oil to an extent insumcient to completely polymerize all of the constituents of the oil, that is, the polymerization is not carried out to such a point that no further decrease in the iodine value can be subsequently attained by a further polymerisation or heat treatment. Partial polymerization contemplates the condensation or polymerization of highly unsaturated compounds without any material or appreciable increase in the molecular size of the less unsaturated or saturated or non-drying glycerides, such as olein and stearin.

Generally stated, the present invention is based upon the discovery that a stream of oil containing a mixture of partially polymerized and unpolymerized glycerides (and containing both drying and non-drying constituents) may he subjected to the action of a countercurrent stream of a use in paints, varnishes, linoleum and wherever a.

drying oil is desired, whereas the other product is eminently suited for use as a non-drying edible in hydrogenation, saponiflcation, salad oils, etc. The drying oils obtained as a result of this process are adapted to produce films which are hard, dense, weather-resistant,

fast-drying, capable of producing a him of great tenacity, and further characterized by the property of gelling completely upon being subsequently heated (polymerizing readily and to a further extent under the influence of heat) so as to form a flexible, resinous, irreversible gel. As a result, the liquid products containing the un-,

saturated drying constituents produced in accordance with this invention can be used as substitutes for Chinawood oil and other expensive and can then be employed in edible products,

soaps, etc. i

It will be evident, therefore, that liquid products of enhanced value can be obtained from oils which are of lower quality or which are not particularly well adapted for a particular contemplated use. It may be said that the present invention is an improvement upon the invention disclosed in my co-pending applicationSerial No. 141,881 filed May 10, 1937.

It"is an object of the present invention,- therefore, to provide a continuous process of treating various oils such as vegetable, animal or marine oils, in normal or partially polymerized condition, for the purpose of producing liquid products of desired composition, characteristics and properties.

Another object of the invention is to disclos and provide a continuous method of separating an oil containing a mixture of glycerides difl'ering in molecular weight into products having mean molecular weights differing appreciably from the mean'molecular weight of the oil origi-- nally treated.

\ A further object is to provide a process of separating in a continuous manner partially polymerized drying oils and unpolymerized non-drying oils from mixtures thereof.

An object of the invention is to disclose and provide a method of producing improved drying oils and improved non-drying oils from mixtures thereof.

A still further object is to provide a continuous method of precipitating polymerized unsatu rated constituents from oils containing the same.

An object is to provide means whereby constituents of drying and non-drying types may be 7 separated in a continuous manner from mixtures thereof.

These and other objects, uses, advantages, adaptations and modifications of the invention will be readily perceived by those skilled in the art from the following detailed. description of A certain exemplary forms of the invention, it"being understood that the invention is not limited to the specific examples, materials and products but contemplates numerous changes and modifications coming within the scope of the invention herein disclosed. In order to facilitate understanding, reference will be had to the appended drawing, in which:

Fig. l is a diagrammatic representation of one arrangement of elementsin which the process of the invention may be carried out. v

Fig. 2 is a diagrammatic representation of a modified arrangement of elements inwhich the process of'this invention may be performed.

Although the process is applicable to the treatment of any oilor mixture of oils, the process i of greatest commercial importance in the treatoils are preferably treated in a partially polymerized state. Soya bean oil is an example of a common semi-drying 011. Such soya bean oils 10 may be polymerized at temperatures of from about 590'F. to 600 F. although temperatures of from about 550 F. to about 610 F. may be used. Polymerization under vacuum is often desirable since an oil of lighter color and lower acid value is thus produced. The heat-bodying or polymerization is conducted in such manner as to cause the minimum amount of gel formation and it is desirable to control the polymerization by observing the drop in iodine .value. The iodine value should not be reduced to a minimum but instead the heat-bodying treatment stopped at such point that the oil, at some subsequent time, is capable of exhibiting a furthertappreciable drop in iodine value upon further heating.

For example, a soya bean oil has been polymerized at a temperature of 590 F. to a viscosity of 90 decipoises. This resulted in raising the refractive index about 80 units, that is, from about 1.4730 to 1.4808 at 50 C. and approximately 50% of the original oil was polymerized. It is to be understood that temperatures of polymerization will vary with the type of oil being treated. For example, soya bean oil requires a higher temper- .ature to obtain the same degree of polymerization as that of hemp seed or linseed oil. In this preliminary partial polymerization the non-drying less saturated glycerides arenot increased in molecular size whereas the drying glycerides are polymerized to increased molecular weights and 40 molecular sizes.

The partially polymerized oil is then subjected to countercurrent treatment with a liquid reagent, preferably in what is termed a precipitating tower equipped with baflles, packing rings,

or other means for insuring thorough countercurrent contact between the oil and reagent ad mitted near opposite 'ends of such tower. The liquid reagent employed should be of a specific gravity differing sufllciently from that of theoil to insure eifective countercurrent flow within the precipitating column. The packing should not result in voids so small as to prevent ready downflow of precipitated oil constituents in drop form.

It has been found that the reagent or precipitant is preferably a ketone or a higher alcohol. Dimethyl ketone, methyl ethyl ketone, diethyl ketone and the higher ketones such as diacetone, butyl and amylic alcohols, primary hexyl, secondary amyl, tetrahydrofurfuryl alcohol and other higher alcohols in primary, secondary and tertiary forms, are examples. Alcohols of higher molecular weight (from the group mentioned) give better results than those of lower molecular weight. It has been further found that the aliphatic hydrocarbons, chlorinated aliphatics and aromatics are not effective.

In my co-pending application which specifiterially smaller volumes of reagent may' be employed, it being found that as low as one volume of reagent. to one volume of oil is capable of tion of another precipitator 28. uid reagent may also be supplied by the proper producing desired results provided, however, the

process is carried out in such manner that at some point in the treatment an excess of the reagent is present .in proportion to the oil.

Referring to Fig; 1, partly polymerized oil from a storage 2 is fed by means of a line 3 to a proportioning pump 4 by introduced into the upper end of a precipitator 6 through a line 5. The precipitator 6 is preferably supplied with means for controlling the temwhich it is supplied and perature therein as, for example, a jacket supplied with steam, hot water, hot oil, or the like.

Liquid reagent from a storage indicated at 8 is supplied by lines 9 and I to the proportioning pump 4 and then introduced in regulated quantity through line H into the lower portion of the precipitator 6. .Countercurrent flow of the liquid oil and liquid reagent is established within the precipitator 6 and'it will be found that a solution of non-drying saturated constituents of the oil in reagent will be discharged from the top of the,

precipitator B as by line l2. 'As shown in Fig. 1, this solution may then which separation is accomplished between the reagent and the saturated constituents or glycerides, these being discharged as by line Minto storage IE or into any other desired form of apparatus in which they may be deodorized, neutralized or hydrogenated, or otherwise treated. The liquid reagent may be discharged from the still l3 as by line l6 into a condenser I1 and returned to storage through the lines it and H. The prdduct collected in storage l will be a bland, non-drying, saturated oil capable of being used for many purposes, suchas edible oil, soap manufacture, etc.

The precipitator 6 will also discharge from the bottom and through line a solution of drying glycerides, mostly glycerides of the unsaturated acids of relatively large molecular size and high molecular weight, together with some reagent, the reagent appearing to be in solution in this drying oil. Such solution of drying oil constituents and reagent may then be fed by a proportioning pump 2| and line 22 into the top por- Additional liqtioning pump 2|.from the storage tank 8 and lines 9 and 23 by line 24 into the lower portion of the precipitator 26. Countercurrent flow .is

again established in this second precipitator, a.

solution of glyceridzs and reagent being d scharged from the top of the precipitator as by line 21. This solution may then be fed to a still 28, the reagent being discharged by line 29 through a condenser and then returned by line 30 and line l9 into storage. The liquid, oily constituents are discharged from the still 28 ash-y line 3| into a storage tank 32. The liquid oil collected in tank 32 will be found to have drying properties. r a

Heavy polymerized constituents together with some liquid reagent will-be discharged from the bottom of the precipitator 26 as by line 33 and this solution may then be pumped as by pump 34 and line 35 into the still 38-whereln separation is accomplished between the liquid reagent and the.

of the oil, composed primarily of polymerized,

glycerides of unsaturated acids and characterized by large molecular size and increased molecular be fed into a still l3 in a substitute for any natural drying oil.

weight, are discharged as by line 39 into the storage 40. 1

In the process just described and illustrated in Fig. 1 it will be seen that a partially polymerized oil may be converted into three distinct products collected in tanks I5, 32 and 40. Tank 40 will contain a liquid oil having greatly enhanced drying properties and capable of being employed as In most instances the drying oil collected in the tank 40 will be far superior to any known natural drying oil and will have the desirable drying characteristics referred to hereinbefore. The liquid oil collected in tank IE will be of the edible, nondrying type. The oil collected in tank 32 will be a drying oil comparable in properties to natural drying oils but it will not have the speed of drying, hardness and tenacity of film which characterizes theproduct collected in tank 40.

Q be very effective. In carrying out the process volumes of acetone per volume of oil.

.with the equipment shown in Fig. 1, the proportioning pump 4 may introduce equal volumes of I oil and acetone into the precipitator 6 although.

it has been fOllIidthEJt better results are obtained by the use of from two, two and one-half or three The first precipitator 6 may operate at a temperature of from F. to F. and preferably about 90 F., whereas the second precipitator 26 is preferably operated at higher temperatures than those found in the first precipitator. When a temperature of 90 F. is employed in precipitator 6, temperatures on the order of about F. may be employed in precipitator 26 with advantage. The

temperatures in the second precipitator, however, should not exceed the boiling point of the liquid reagent used and in the case or acetone should not exceed about 132 F. since the system is not maintained under pressure.

Within the precipitator 6 two separate solutions appear to be formed; one of the solutions formed comprises a solution of glycerides of low molecular weight (non-drying type) dissolved in the liquid reagent, this solution being discharged from the top by line l2. The heavy polymerized drying constituents dissolve in the reagent and are capable of dissolving larger quantities of reagent at higher temperatures. As a result. the

-solution discharged by line 20-from the bottom of the precipitator 6 is. a solution of reagent in drying constituents. at intermediate points these two solutions appear to be mutually soluble within limits so that I such all in a part of the total volume of liquid reagent to beusedbefore introducing the oil into the precipitator as by line 5. Additionalreagentis then supplied byline II. The solution of reagent in glycerides discharged by line 20 into the precipitator 26 is preferably .treated with reagent (supplied by line 24) in volume sufficient to produce a ratio of not less than about one volume of reagent to one volume of actual 'oil' and preferably a ratio of two to three volumes of reagent to one volume of actual oil. allowance being made for the volume of reagent-carried by glae oil discharged from the precipitatori by line Within the precipitator 6 Furthermore, attention is called to the fact that in commercial operation the amount of oil carried by the reagent discharged from the top of the precipitator by line l2 should preferably not exceed about 20% of the total volume 01 such outflow.

In a specific example, a partially polymerized semi-drying oil was fed into a precipitator. such as the precipitator 6, at a rate or 0.305 gallon per minute. The precipitator was maintained at atemperature 01 about 80 F. Acetone was fed into the lower portion of the precipitator at the rate of about 0.757 gallon per minute. The discharge from the top of the precipitator was at the rate of 0.791 gallon per minute and 46% of the total oil fed into the precipitator was discharged through the top conduit (such as the conduit I 2), this fraction or oil being in solution in the reagent. Actually, the solution being discharged from the top of the precipitator comprised 18% oil and 82% reagent and the oil had a refractive index of 1.4725.

The oil discharged from the bottom of the precipitator was removed at the rate or 0.271 gallon per minute and this discharge contained 54% of the total oil fed into the system The discharge from the bottom of the precipitator consisted 01' 61% oil and 39% acetone. The oil dischargedfrom the bottom or the precipitator had a refractive index of 1.4864. v

Attention is' called to the fact that the partially polymerized oil originally fed into the precipivtator had a refractive index of 1.4800 whereas the two products obtained hadirefractive indices as stated in the following table:

' Sample Acetone -Oil R I. of oil 7 Percent Percent At overflow 82 18 l-. 4725 1 82 18 l. 4737 2 87 13 1. 4740 3 89 11 1. 4740 4 9i 9 1. 4750 5 95 5 1. 4762 At discharge. 39 61 l. 4864 The samples were taken from top to bottom and are so arranged in the table. Attention is called to the fact that the character of the rising oil in solution at the various levels of the precipitaitor difiered markedly as indicated by the refractive index of the 011.

By referring to Fig. 2 it. will be seen that in the modified form of process oil and reagent are fed into the precipitator 6' in a manner similar to that described in connection with Fig. 1. The precipitator 6' is, however, preferably maintained at a higher temperature, that is,.at a temperature: ranging from say 110' F. to 130' F. It is to be noted that this temperature is below the boiling point or critical temperature of the reagent, in this instance acetone. The solution of the unsaturated non-drying constituents in acetone is discharged iron: the top of the precipitatcr 6' as by line 42 into a cooler 43 and then supplied to a separating column ll provided with suitable means for maintaining-a desired temperature in such column. By reducing the tem-' perature or this solution, a part of the constituents of the oil are precipitated in liquidtorm.

The glycerides precipitated are those of heav ier molecular weight. These precipitated glycerides are removed from the bottom or the separator u as by line 4: and sent too can u wherein separation is accomplished between the oil and the acetone. The oil is then discharged from tion of a precipitating column; introducing a Those saturated, low molecular weight, small- I molecular size glycerides which remain in solution in the acetone are discharged from the top of the separator 44 as by line 54 into a still 55 wherein the acetone is distilled ofl, permitting the discharge by line 56 of a non-drying saturated oil which may then be collected in the tanl: 51. The acetone is dischargedfrom the still 55 as by line 58 into-a condenser 59 and returned to storage by lines 60 and 52. The heavy unsat urated drying constituents precipitated in 6' are discharged by line 62 into a still 63 wherein by distillation separation is effected between the drying oil and-the acetone. The drying oil is vdischarged byline 64 into thetank 65, the acetone being discharged by line 66 into condenser 81 and then by line 68 back to storage.

Inthe performance of this process it is to be understood that instead or using a continuous separating column I, a batch operation may be performed by tank storage cooling.

Although in the examples'g'iven three products were produced from the original oil treated, it is to be understood that the process may be employed in the production oi two or more separate products from a given oil. Moreover, it is tobe noted that the reagent, such as acetone, is

recovered and may be used in cyclic operation of the process withvvery minor losses. I

Those skilled in the art will understand that valves, temperature regulating devices and other attachments are appropriately installed in the manner well known ;to chemical engineers but that such devices have not been shown on the drawing in order to facilitate understanding and prevent confusion. j I

I claim:

1. In a process of treating vegetable andmarine oils, the steps or: introducing an oil havingpolymerized highly unsaturated drying constituents and unpolymerized non-drying less unsaturated and saturated constituents into the upper pornormally liquid reagent from the group consisting of ketones and butyl alcohol and higher alcohols into the lower end of such precipitating column, at a volumetric rate not lower than the rate at which oil is introduced; continuously withdrawing reagent containing unpolymerized non-drying constituents in solution from the top of said precipitator; continuously withdrawing unsaturated polymerized drying constituents containing reagent in solution from the bottom 01' the precipitator; and separately purifying each of the withdrawn solutions to produce a liquid oil containing unpolymerized non-drying constituents in major proportion and another liquid oil containing polymerized drying constituents in major proportion.

2. In a process of. treating vegetable and marine oils, the steps of: introducing an oil having polymerized drying constituents and unpolym'erized non-drying constituents. into the upper portion of a precipitating column: introducing acetone into the lower end of column at a volumetric rate twice the rate at which oil is introduced; continuously withdrawing acetone containing non such precipitating not lower than polymerized constituents containing acetone in solution from the bottom of the precipitator; and separately purifying each of said withdrawn solutions for the removal of acetone therefrom so as to produce two separate liquid oil products.

3. In a process of treating vegetable and marine oils, the steps of: introducing an oil having polymerized drying constituents and unpolymerized non-drying constituents into the upper portion of a precipitating column; introducing a liqand butyl alcohol and higher alcohols into the lower end of such precipitating column. at a volumetric rate not lower than the rate at which oil is, introduced; continuously withdrawing reagent containing non-drying constituents in solution from the top of said precipitator; continuously withdrawing polymerized drying constituents containing reagent insolution from the bottom of the precipitator; and separately purifying each of the withdrawn solutions.

4. In a process of treating vegetable and marine oils, the steps of: introducing an oil having polymerized drying constituents and unpolymerized non-drying constituents into the upper portion of a precipitating column; introducing a liquid reagent from the group consisting of ketones and butyl alcohol and higher alcohols into the lower end of such precipitating column, at a volumetric rate not lower than the rate at which oil is introduced; maintaining said precipitating column at below the boiling point of the reagent; continuously withdrawing reagent containing a mixture of drying and non-drying constituents in solution from the top of said precipitator; constituents' containing reagent in solution from the bottom of the precipitator; and separately puritying each of the withdrawn solutions by subjecting the withdrawn polymerized constituents containing reagent in solution to distillation, and,

by separately treating the solution "withdrawn from the top of the precipitating column by cooling the same to precipitate drying constituents from the remaining solution of non-drying constituents, and then subjecting the remaining solution to distillation to remove reagent therefrom. v

5. In a process *of treating vegetable, and marine oils. the steps of introducing an oil having polymerized drying constituents and unpolymerized non-drying constituents into the upper portion a precipitating column; introducing a liquid reagent from the group consisting of ketones and butyl alcohol and higher alcohols into the volumetric rate not lower than the rate at which oil is introduced; continuously withdrawingrreagent containing non-drying constituents in solultion from the top of said precipitator; continuously withdrawing p lymerized dryin -constituents containing reagent in solution from the bottom oft-he precipitator; and separately puritying .each of the withdrawn solutions by sub jecting the polymerized constituents containing reagent in solution and withdrawn'from the bottom of the precipitator to a further countered!- rent treatment with additional reagent, and by separately purifying the solution withdrawn from the top of the precipitator.

6, In a method of treating vegetable and marine oils, the stepsof: subjecting an oil containing drying and'non-drying constituents to partial polymerization; adding a normally liquid reagent from the group consisting of ketone,

from the same group of reagents into the lower portion of the precipitator; maintaining said precipitating column at below the boiling point of the reagent; continuously withdrawing reagent containing non-drying constituents in major proportion from the top of the precipitator; conuid reagent from the group consisting of ketones tinuously withdrawing a solution containing drying constituents in major proportion from the bottom of said precipitator; and separately purifying each of the solutions so withdrawn.

l5 '7. In a method of the character described, the

steps of subjecting an oil containing drying and non-drying constituents to partial polymerization; adding acetone to said partially polymerized oil to form a solution; continuously -introducing such solution into the upper portion of a precipitator; continuously introducing additional acetone into the lower portion of the precipitator; continuously withdrawing acetone containing non-drying constituents in major proportion from the top of the precipitator; continuously withdrawing drying constituents containing some acetone from the bottom oi said precipitator; and separately purifying each of the solutions so withdrawn.

8. In a method of the character described,

the steps of subjecting an oil containing drying and non-drying constituents to partial polymerization; introducing such oil into the upper portion of a precipitator; introducing a normally liquid reagent from the group consisting tinuously withdrawing polymerized drying con- Q at a temperature below the boiling point of the reagent; continuously withdrawing reagent containing non-drying constituents in major proportion from the-top of the precipitator; continuously withdrawing a solution containing drying constituents in major proportion from the bottom of said precipitator; and separately purifying each of the solutions so withdrawn.

9. In a method of the character described, the steps of subjecting an oil containing drying and non-drying constituents to partial polymerization; introducing such oil into the upper portion of a precipitator; introducing a normally liquid reagent from the group consisting of ketones and butyl alcohol and higher alcohols into the V lower portion of such precipitator at a volumetric lower end of such precipitating column, at a rat not lower than the rate at which oil is introduced; maintaining said precipitator at a temperature below the boiling point of thereagent; continuously withdrawing reagent containingnon-drying contituents in major pronon-drying constituentsremain in solution; re-

moving the precipitated drying constituents-from the remaining solution; separately purifying said remaining solution to produce a liquid oil composed essentially of non-drying constituents; and

continuously withdrawing drying constituents from the bottom of said first named precipitator.

10. In a process of the character described in claim 12, the further steps of separating reagent from th lower molecular weight glycerides with- 5 drawnfrom the top of the precipitator by subjeoting the withdrawn solution to settling at a lower temperature than that in the precipitator whereby a portion of said glycerides is precipi tated and another portion remains in solution in the reagent; and then separating reagent i'rom withdrawing a solution of glycerides of lower molecularweight from the top of said settling zone, and then separately purifying said solution to remove glycerides therefrom.

12. In a method of the character described, the steps of: introducing a partially polymerized oil comprising a liquid mixture of glycerides varying in molecular weights into the upper portion of a precipitator; introducing a normally liquid reagent from the group consisting of ketones, butyl alcohol and higher alcohols into the lower portion 01' said precipitator; continuously withdrawing glycerides of higher molecular weights from the bottom 0 the precipitator, and continuously withdrawin reagent containing glycerides of lower molecular weight from the top of the precipitator.

l3. In a process of the character described, the. steps oi: subjecting a flowing stream of partially polymerized oil containing a mixture 01 low and high molecular weight glycerides to the action of a countercurrent stream oi! normally liquid reagent from the group consisting of ketones, butyl alcohol and higher alcohols, in a contact zone, said reagent having a specific gravity differing from that of the partially polymerized oil; maintaining said countercurrent flow at a controlled temperature below the boiling point of the reagent; continuously discharging reagent containing glycerides oi. low molecular weight in major proportion from the top oi. said zone, and separately discharging glycerides of higher molecular weight from the bottom of said zone.

OTHO M. BEBE.

Images