GLYCEROL Newer Developments and Possibilities T H E return of glycerol to its prewar status has stimulated interest in a large number of applications which, when t h e war began, were more or less experimental. N o w that government restrictions have been removed and glycerol is in plentiful supply it is well worth while t o study the varied role it plays in modern industry. Merely listing some of glycerol's properties will suffice t o indicate the reasons for i t s utility in literally thousands of products. Thus it can be made t o serve as: a humectant or hygroscopic agent, a solvent, a vehicle, a "bodying" agent, a suspending agent, a lubricant, a heattransmitting material, a pressure-transmitting agent, an antifreeze, a softener and plasticizer, a sweetener, a penetrant, a n emollient, and a blending agent. Glycerol m a y b e employed in a composition because i t supplies just one of these characteristics, but more generally it furnishes two or more simultaneously. Use în A Ik y d Resins On the other hand, its chemical properties make its reactive functions almost as important as i t s physical properties. As a polyhydric alcohol with three hydroxyl groups it is capable of forming many linkages and m a n y valuable derivatives. Among the m o s t important of these are t h e alkyd resins, ester gums, and nitroglycerine. Current indications point to far greater utilization of glycerol as a chemical substance, with particular emphasis on new, better, and more widely useful alkyd resins. Indeed, more glycerol was used in t h e production of resins and ester gums during 1943 than in any other consuming industry (44)' Despite many new developments, the reaction products of glycerol and phthalic anhydride, suitably adjusted with a variety of modifying agents, still remain the basis of t h e alkyd type of synthetic resins. Holding a position uniquely their own, the alkyd resins have proved indispensable in the formulation of modern synthetic coating materials. Used alone or in combination with nitrocellulose, phenolic resins, or urea resins, the alkyds h a v e found extensive use in quick-drying, durable interior and exterior finishes, in automobile and refrigerator enamels and lacquers and, a t present, in all types of protective coatings for the armed forces and adjunct agencies (70). V O L U M E
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The "why" of glyceryl-phthalate resins in government specification finishes has been answered in recent months by many authorities (S, 23,59). Briefly, the alkyds have supplied the desirable speed of application, toughness, durability, flexibility, color retentiveness, and beauty required of modern finishes. Their proved ability to stand up under really severe conditions points definitely to the wider use of the alkyds in the postwar period (73). Among the new developments in prospect are use in water- and ice-repelling coatings (5) and in simulating hammered metal finishes (11). Known for some years but really wardeveloped in their present wide usage are the emulsion-type paints based upon aqueous dispersions of alkyd resins. These paints find increasing utility in exterior paints for cement, concrete, cinder blocks, and similar surfaces; their quick-drying properties and freedom from odor have made them extremely popular as interior wall paints for offices and homes (56). Progressive research and development have extended the usefulness of the glyceryl phthalate resins to many fields. T h e textile industry particularly has benefited from the increasing use of these alkyd resins (41)- A listing of the properties of the group, which make them suitable for textile use, has been presented in Cleaveland's (12) review on textile plastic coatings in the postwar era. Actually, the alkyds have already found many important uses in a variety of textile finishes (14, 24)· For example, a triethanolamine-modified glyceryl phthalate resin, used in conjunction with a urea-formaldehyde resin, has recently been advocated for treating cellulosic yarns and fabrics to render them heat-, acid-, and alkali-resistant (3, 52). Illustrating the way that the alkyds can help meet present and possible future needs for hard-to-get materials, are a report and a patent from England, where the use of a glyptal-treated rayon fabric has been sanctioned officially as a substitute for oiled silk, an essential in wound dressings (4). I n the patented process, the production of bolting cloth from artificial threads calls upon the use of a similar alkyd resin to maintain the integrity of the sieving openings and to heighten the general efficiency and long life of the finished apparatus (15).
2 2 « N O V E M B E R
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Georgia Leffingwell and Milton A . Lesser 11 West 42nd St., New York 18, Ν . Υ.
In addition to their growing utility in fabric coatings, the alkyds have found increasing employment in compositions for the printing and dyeing of textiles. In some methods patented during the last year or so, the alkyd is the chief resinous component of the coloring ma terial (22, 4&)', in others it is used in conjunction with other synthetic resins (SO, 83, 84). Glycerol is firmly entrenched as a major raw material of the paper industry and its resinous derivatives also have im portant uses in paper coatings, impregnat ing and sizing materials, etc. (9, 87). Of interest in this connection is the further expansion of both glycerol (21) and glyc eryl phthalate resins (18) into the formu lation of new printing inks. T h e alkyd-type -resins have been speci fied in an increasing number of patents for making photographic films, including color photography (17, 47) as well as in "self-developable" photographic emul sions (35). In former years, the slow curing time of the alkyds militated against their wide use as binders for molded products, except under specific conditions. Today this picture seems to be reversing itself, for one finds in the patent literature increasing references to alkyds in conjunction with other synthetics, more especially the phenolformaldehyde condensation prod ucts, for making moldable resins (26). In one recent instance (27), such a phenolformaldehyde-glycerol-phthalic anhydride combination was specified for forming clear, colorless resins for making cast products. The alkyds have been recom mended also as binders for materials other than synthetic resins (7, 69), for uses in special sealing compositions for cans and containers (55), and in new calking com pounds suitable for sealing the joints of airplanes, fuel tanks, and the like (2).
Glycerol as Plasticizer Turning now to t h e ' more familiar physical properties of glycerol, one finds that i t is rather extensively employed as a plasticizer for polyvinyl alcohol now 2009
having wide use in the form of molded or extended articles, films, and imprégnants (16, 31). Of course, glycerol has a very similar, but longer established, role in the production of cellulosic products, more especially cellophane. Indeed, millions of pounds of glycerol are needed to plasticize these widely used transparent sheets, and keep them from becoming brittle. There are indications .also that glyceroltoughened cellophane may have many newer uses (64)Schwartz (63) of the U. S. Public Health Service has pointed to another important potential use for cellophane plasticized with glycerol. He recommended it for protective clothes for workers, because it is not affected by acids or petroleum solvents and guards the wearer against certain toxic gases. Inflammability and the tendency of cellophane to become brittle when wet, could be overcome by known procedures. As a matter of fact, glycerol has been employed in processes for flame-proofing these cellulosic materials (72) and an alkyd has been used in methods for rendering them moistureproof (29). Glycerol has a well-established and broadening role in the textile field, as is evidenced by many reports (39, 40) and especially by the progressive reviews published annually in the Rayon Textile Monthly (38). It is extensively employed in sizing compositions, lubricants, finishes, dye baths and printing pastes, and in many specialties, including a Russian substitute for asbestos cloth used as protective curtains in electric welding and similar industries. According to Abramovich (I), fabric for this purpose is first fireproofed b y saturating it with a 2 0 % solution of ammonium phosphate. After drying, the cloth is coated with three layers of the following solution, with intermittent drying periods between applications of each layer: casein, 100 parts; water, 400 parts; glycerol, 130 parts; ammonia (25% solution), 10 parts. If 500 parts of water glass (sp. gr. 1.35 to 1.40) are added to the above mixture after homogenizing, the preliminary saturation with ammonium phosphate may be omitted. Thin or transparent fabrics may be opacified by adding 30 to 50 parts of zinc oxide or soot. Curtains made in this way proved more resistant than impregnated fireproof tenting canvas. Long used in certain electroplating and electrostripping solutions and a standard ingredient in the anodic coloring of aluminum, glycerol finds growing employment in electro-polishing methods, particularly in the field of electro-polishing stainless steel. In a recent review, Wernick (71) cites Uhlig in 1940 as the first to demonstrate the superiority of the phosphoric acid-glycerol system over the sulfuric acid process for electro-polishing stainless steels. Glycerol serves also in electrolytic methods for brightening and polishing
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other metals. It may be used, according to* a British description (48), in solutions fo»r the anodic polishing of magnesium and magnesium-base alloys, while an iV^merican process (20) uses substantial pEToportions in a sulfuric acid bath for eL-ectro-polishing German silver, iron, nickel, or their alloys. Other European sfciulies (58) on sulfuric acid baths for eHrcctroplating and anodizing have shown· ttnatthe deposition from ferrosalt solutions i s favorably influenced b y the addition off glycerol. In the meantime, newer jKToccsses for the anodic coating of aluminium a n d its alloys (10) and for the claromium plating of metals (66) have included glycerol as an important constituent of the plating baths.
The Food Field The food field especially offers important possibilities for glycerol. A nonnal constituent of the body, as a result of fat cligcstion, and naturally present in ferGneiited beverages such as wine and beer, glycerol has long been employed as a safe, uvholesome component of many prepared fzoods and beverages. Here, owing to its scientifically proved purity and suitaEbility for human consumption it is in a «olass î>y itself. An excellent solvent and Iblending agent, it is used by the ton in *he manufacture of base flavors for many food products, including soft drinks. The value of glycerol for producing abetter baked goods that stay fresh longer a s appreciated by English bakers who Uiave used it extensively for many years. •Our o w n food technologists have been sslow&r in recognizing its value. Glyceriznatecl eggs and egg yolks, however, have •come in for extensive investigation and American workers have confirmed the rather empirical methods of the English. Woodroof (77), for example, at the Georgia Experiment Station showed in cake-baking experiments that frozen whole eggs with 3% glycerol gave a smoother, finer, more even grain than either fresh or frozen eggs without glycerol. Other studies point to the extension of glycerinated egg-yolk as a logical postwar development (45) and there is evidence that such eggs may be advantageously used by the housewife as well a s by the large food processor (62). W-ell on its way as a result of proved wortli in extensive field studies, the quickfreezing of foods by immersion in a glycerol medium was held in abeyance for the duration. Careful investigations indicated that glycerol was a suitable medium for immersion freezing (78) and these * led to more extensive practical work proving the efficiency, mobility, and economy of the process (SO). Progress in this field to date warrants the statement that the immLersion freezing process based on the use of glycerol solutions merely awaits the availability of materials required for building the necessary equipment.
CHEMICAL
M e d i c i n a l Preparations Next to water, glycerol probably is the most important solvent used in the preparation and dispensing of medicinal preparations for both internal and external use. Nowhere is this more evident than in the local or topical application of the sulfonamide drugs for treating wounds, burns, and dermatological conditions. Laboratory and clinical investigations reported in 1941 started these studies which established glycerol as a superior sulfa vehicle. In England, Locatelli and Bowden (42) checked the action of sulfanilamide in a series of vehicles and found that a suspension in glycerol gave the largest area of bacteriostasis, even larger than the owdered drug itself. I n the United tates, Lain (36) found that no vehicle gave such good results in a variety of dermatological conditions as did glycerol used alone. In the same year, British surgeons (61) developed a sulfonamideglycerol paste for the treatment of burns. Other workers (32, 67) confirmed these findings, among the most recent reports being those of Wood (75, 76) who strongly advocated the use of a "sulfathiazole and glycerine cream 30%" for treating à variety of wounds, burns, and infections and for preoperative preparation of the skin. In instances where glycerol is not the chief vehicle for the sulfa drugs, its use in the topical preparation is considered an important adjunct (13, 19, 57, 68). Glycerol-sulfonamide combinations also have found important uses in dentistry and oral surgery (51).
g
Glycerol serves as a plasticizer in the newer film-forming preparations containing sulfa drugs and depending upon methyl cellulose or polyvinyl alcohol for their film-forming properties (28, 65). Sterile glycerol itself has found a most important role in treating burns of the hands and face, where tough film or eschar formation is to be avoided (46). Another noteworthy development of the last year or so has been the use of glycerol in epinephrine (adrenalin) inhalant sprays for the prevention or treatment of asthmatic paroxysms. The addition of glycerol to such solutions provides not only a finer and more efficient spray (54) > but a better solution with a more marked therapeutic effect and with less undesired side actions (43, 74)- A superior epinephrine solution containing glycerol for injection also has been developed (53). Solutions of new vaso-sulfa compounds (desoxyephedronium sulfathiazole) for treating sinusitis and other nasal infections can be stabilized with sodium suinte υ,τΛ glycerol (25). Two other recent glycerol uses in medi cine should be mentioned: in the pro duction of clear, soluble protamine zinc insulin (6), and as a media component for making penicillium-inoculated bandages to secure the local benefits of penicillin for certain of wounds and infections (60). This listing of the new glycerol develop ments of the last year or two, explains why science has been unable to find any com plete substitute for this versatile fluid. Its CONTINUED ON PAGE 2 0 4 4
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Glycerol (CONTINUED HiOM PAGE 2 0 1 0 )
wide possibilities can be summed up in the c o m m e n t of one chemist: " W h e n we're s t u m p e d , we always try glycerol. Y o u ' d be surprised how often it w o r k s . "
Literature Cited (1) Abramovlch, A. F. t Avtogennoe Delo, 12, No. 5, 12 (1941). (2) Acker, H . L.f TJ. S. Patent 2,325,726 (Aug. 3 , 1943). (3) Angus, G. & Co., and Balkin, M. f British Patent 551,513 (Feb. 25, 1943). (4) Anon., Pharm. J., 150, 46 (1943). (5) Armentrout, G. E., U. S. Patent 2,316,041 (Apr. 6, 1943). (6) Bailey, C. B. f and Marble, Α., J. Am. Med. Assoc, 118, 683 (1942). (7) Bakélite G. m. b. H., German P a t e n t 721,916 (May 14, 1942). (8) Beaman, J. R., Domestic Commerce, p. 7 (May 1943). (9) Buccar, M . de, Papeterie, 63, 201 (1941). (10) Byrne, C. R., British Patent 548,862 (Oct. 28, 1942). (11) Canter, R. t and Geyer, H. D., British Patent 548,106 (Sept. 25, 1942). (12) Cleaveland, J. B., Textile World, 93, 59 (May 1943). (13) Cole, H. N., J. Am. Med. Assoc, 123, 411 (1943). (14) Corteen, H., U . S. P a t e n t 2,307,876 (Jan. 12, 1943). (15) Courtaulds, Ltd., and McFarlane, R . A. British Patents 557,486; 557,487; 557,488 (1943).
Producers
of
SULPHUR Large stocks carried at all times, permitting prompt shipments . . . Uniformly h i g h purity oi 99Vi% or better . . . Free oi arsenic, s e l e n i u m a n d tellurium.
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(16) Dangelmajer, C , U. S. Patent 2,340,866 (Feb. 8, 1944). (17) Elliot and Sons, Ltd., and Howe, D . J. T . , British Patent 536,329 ( M a y 12, 1941). (18) Erickson, E>. R., and Thoma, P . J., TJ.S. Patent2,313.32S (Mar. 9, 1943). (19) Evaas» C. H., J. Am. Pharm. Assoc, Tract. Pharm. Ed., 3, 235 (1942). (20) Faust, C. L., U . S. Patent 2,315,695 (Apr. 6, 1943). (21) Gessler, A. E., U . S. Patent 2,335,505 (Nov. 30, 1943). (22) Gesslei\ A. E., and Pizzarello, R. Α., U.S. Patent2,309,946 (Feb. 2, 1943). (23) Glaser, Μ. Α., Ind. Finishing, 19, 52 (Oct. 1943). (24=) Gurley, Μ . Η . , Jr., Rayon Textile Monthly, 23, 726 (1942); 24, 34 (1943). (25) Hamilton, W . F . , George, M . P „ Jr., Simon, E . t and Turnbull, F . M., J. Ant. Pharm. Assoc, 33, 142 (1944). (26) Hansen, 0 . , Canadian P a t e n t 414,511(Aug. 10, 1943). (27) Hansen, O., U. S. Patent 2,289,266 (July 7, 1942). (28) Harkins, H . N., Illinois Med. J., 84, 103 (1943). (29) Heaven, G. S., and Berry, W., U. S. Patent 2,311,831 (Feb. 23, 1943). (30) Johnson, M . W., U. S. Patent 2,310,436 (Feb. 9, 1943). (31) Jones, J. I., Brit. Plastics, 14, 122 (Max. 1944). (32) Kiila, F . , and Frinz, M . V. N., Canadian Med. Assoc. 7T, 46, 457 (1942). (33) Kionle, R. H., and Peiker, A. L., Cana dian Patent 411,395 (Mar. 30, 1943). (34) Klinkenstein, G-. and Frey, C., U. S. Patent 2,336,484 (Dec. 14, 1943). (35) Knott, E. B., U . S. Patent 2,315,966 (Apr. 6, 1943). (36) Lain, E . S., Arch. Derm. Syph., 44, 257 (1941). (37) LeiïingAveil. G., and Lesser, Μ . Α., Paper Ind. Paper World, 25, 44 (Apr. 1943). (38) Leflingwoll, G., and Lesser, Μ . Α., Rayon Textile Monthly, 19, 318, 379 (1938); 20, 517 (1939); 2 1 , 553, 635 (1940); 22, 532 (1941); 23, 550 (1942); 24, 493, 543 (1943). (39) Leflingwell, G., and Lesser, Μ . Α., Textile Age,- 8, 3S (Mar. 1944). (40) Leffingwell, G., and Lesser, Μ . Α., Textile Coloriât, 62, 743 (1940). (41) Leffingwell, G., and Lesser, Μ . Α., Textile Research (in press). (42) Locatelli, A. M., and Bowden, S., Pharm. ./., 146, 251 (1941). (43) Lockey, S . D . , J. Allergy, 14, 382 (1943). (44) McConlogue, W . Α., and Lenth, C. W., Soap, 20, 34 (May 1944). (45) McFa-rlane, V. H., and Hall, Η . Η., Agr. Chem. Research Div., U. S. Dept. Agr. Chem. Eng. Paper 102; Food Materials and Equipment, p . 11 (June 28, 1943). (46) Mackenzie, W . C., Canadian Med. Assoc. jr., 47, 443 (1942).
(47) McQneen, D . M . , U. S. P a t e n t 2,290,289 (July 2 1 , 1942). (48) Magnesium Metal Corp., Ltd., and Pearson, W. K. J., British P a t e n t 550,175 (Dec. 28, 1942). (49) Mantell, C . L., V. S. P a t e n t 2,311,850 (Feb. 2 3 , 1943). (50) Mauldin, E., Food Industries, 13, 46 (Oct. 1941). (51) Meacham, P. L., and Osgood, Ε . Ε., / . Am. Dental Assoc, 28, 1640 (1941). (52) Monsaroff, B., U. S. P a t e n t 2,341,735 (Feb. 15, 1944), (53) Waterman, H . L.f New England J. Med., 12, 227 (1942).
CHEMICAL
(54) N. Y. State J. Med., 43, 1224 (1943). Symposium. (55) O'Leary, L. C , U. S. P a t e n t 2,326,966 (Aug. 17, 1943). (56) Pearce, W. T., Paint, Oil Chem. Rev., 105, 24 (June 5, 1941). (57) Pillsbury, D . M., Wammock, V. S., Livingood, C. S., and Nichols, A. C. f Am. J. Med. Sci., 202, 808 (1941). (58) Piontelli, R., Korrosion u. Metallschutz, 19, 110 (1943). (59) Reizenstein, L. J., Paint, Oil Chem. Rev., 106, 11 (June 4, 1942). (60) Robinson, G. H., and Wallace, J. E . , Science, 98, 329 (1943). (61) Robson, J. M., and Wallace, A B . , Brit. Med. J., 1, 469 (1941). (62) Schaible. P . J., and Card, C. G., Food Industries, 15, 67 (May 1943). (63) Schwartz, L., N. Y. State J. Med., 42, 1525 (1942). (64) Self, S. B., Wall Street J. (Feb. 16, 1942). (65) Skinner, H . G., and Waud, R. Α., Canadian Med. Assoc J., 48, 13 (1943). (66) Spence, J. W., U. S. P a t e n t 2,327,676 (Aug. 24, 1943). (67) Stedman, H. E., U. S. Naval Med. Bull., 41, 1118 (1943). (68) Veal, J. R., and Klepser, F . G., Surgery, 10, 947 (1941). (69) Voskerenskiï, P . I., and Poroshin, K . T., Khim. Referai. Zhur., 4, No. 4, 123 (1941). (70) Wakeman, R . L., and Weil, Β. Η . , Ind. Eng. Chem., 34, 1387 (1942). (71) Wernick, S., Canadian Metals Met. Inds., 7, 29 (Mar. 1944). (72) White, W. D . , U. S. P a t e n t 2,316,496 (Apr. 13, 1943). (73) Whitecarver, W. F . , Paint Ind. Mag., 59, 66 (1944). (74) Wilcox, R., Pharm. J., 151, 69 (1943). (75) Wood, Ε. Η., Canadian Med. Assoc J., 50, 251 (1944). (76) Wood, Ε . Η., Clin. Med., 50, 231 (1943). (77) Woodroof, J . G., Ice & Refrigeration, 52, 62 (1942); Bakers Digest, 16, 134 (Feb. 1942). (78) Woodroof, J . G., Refrig. Eng., 24, 584 (June 1929).
Odorless Household Fly Spray Chemists in the Agricultural Research Ad ministration, U. S. Department of Agricul ture, Beltsville, Md., have perfected an odor less and nonirritating household fly spray t h a t will be less likely to produce irritating rashes or hay fever symptoms, which have limited its use in the past. Three chemists in the Bureau of Entomol ogy and Plant Quarantine, W. F . Barthel, H . L. Haller, and F . B . LaForge, discovered a new and simple method by which nitromethane can be used to produce practically pure pyrethrins from the impure petroleum extract of pyre thrum flowers. The new solvent takes out practically all of the py rethrins, the toxic ingredient in these in secticides, but leaves most of the irritating impurities in t h e petroleum solvent. T h e nitromethane solution is passed through char coal to remove any remaining irritating m a terial. The nitromethane is then distilled off, leaving practically pure pyrethrins, with no irritating residues. Used in the aerosol bomb, this aerosol promises to be a n effective postwar weapon against flies and other household pests.
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Scholarships Awarded Science Talent Search Winners Scholarships worth almost S82.500 have been awarded the 300 winners of the secortd annual Science Talent Search, completed £ n 1943, to help them through their first year o f college. This amount is the total granted h»y colleges and universities, exclusive of SI 1,000 in Westinghouse Science Scholarships, awarded as a direct result of the Science Talent Search. The fourth annual search is already und«er way. A difficult, two-hour science aptitude examination is now being mailed to more than 3,000 high school principals and teadiers, who will administer it to entrants in their home town high schools. The science aptitude examination, desigiued to test the ability of the student to think acid observe, rather than his scientific knowledge, will be given between Dec. 1 and 27.
How to Produce
MIXTURES RAYMOND Roller Mills, I m p Mills and Screen Pulverizers provide a n effective m e t h o d of obtaining a complete and thorough intermixture of ingredie n t s in finely powdered form. With suitable feeders for proportioning t h e several materials to the mill, the finished product is delivered with an i n t i m a t e dispersion of the particles . . . in t h e correct mixture and t o specified fineness. The Raymond s y s t e m , either w i t h or without air separation, is successfully used in blending t h e various ingredients i n face powders . . . also for t h e mixing of t h e conditioning and wetting agents w h e n grinding sulphur for insecticide spray purposes . * . blending p i g m e n t s . . . making food products mixtures . . . introducing flavoring m e d i a , extenders and free-flowing admixtures.
Training Engineers As an answer to the problem of adequately training engineers for the leadership tbtey will eventually assume, Cornell University will require five years instead of the conventional four for a bachelor's degree in a.11 branches of engineering after the war.
An approximate rise of 20% in enrollment was made by Illinois Institute of Technology in the new term which started on Nov. 2~ Of the 2,077 total enrolled in day E*nd evening classes for the term, 62 are returned veterans of World War II, who are in attendance as civilian students. The Navy V-12 unit now totals 398 men, many vetersans of active duty during the present war.
RAYMOND IMP MILL for grinding coal and salt mixtures, coal
Responsibility of management in -the rehabilitation of veterans has been summed \ip b y the National Association of Manufacturers' Committee on Supervisory ZEtelations. New York.
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R A Y M O N D ROLLER M I L L | for pigment and talc pulverizing • . · also for many other n o n metallic minerals and manufactured products.
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R A Y M O N D SCREEN P U L V E R I Z E R for grinding and blending colors, dyestuffs, food products and many similar materials.
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Canada: Combustion Engineering C o r p . , Ltd., Montreal Your country is still at war—«re y o u ?
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