66 CHEMISTRY mining the atomic weight of the radium emana- connected with this subject, it has been known tion. Debierne's paper forms one of the most for many years that if membranes through which beautiful experimental contributions published water alone can pass, but which are impermeable in the course of the year. Since the emanation to substances that may be dissolved in the forms no chemical compounds, its atomic weight, water-if such membranes are interposed between like that of argon, could only be found by deter- some solution on the one hand and pure water mining its density. Ordinarily, the determina- on the other hand, the pure water will pass tion of the density of a gas presents no particular difficulty, that is, when there is a considerable amount of the gas available. In the case of the emanation, however, the amount is exceedingly slight, and the difficulty of measuring its density is correspondingly great. All ordinary methods, involving determinations of both the volume and weight of gas, are entirely out of the question. Debierne made use of the method originally invented by Bunsen and not infrequently used for rapid measurements by industrial chemists in illuminating-gas works. The method consists in allowing the gas to escape from one chamber into another through a fine pinhole and measuring the rate of escape. The rate of escape informs us of the density of the gas, from which the molecular weight may be readily computed. In the case of the emanation, as in that of argon, helium, and the other monatomic gases, the atomic weight is simply equal to the molecular weight. But Bunsen's method, too, involves the employment of considerable amounts of gas, and Debierne's contribution consisted primarily in so modifying and refining Bunsen's method as to render it usable with very small amounts. Debierne finally succeeded in transferring one cubic millimetre of the emanation into one of the two chambers of his apparatus, closing it up under a pressure of only one one-hundredth of a millimetre of mercury, then establishing pinhole communication with the second chamber, in which the pressure was continually maintained with the aid of a rapid-acting mercury pump, as as possible. The atomic weight of the radium emanation thus found was 220. According to theory, the atomic weight should be 222.5, that is, four units less than 226.5, which is the atomic weight of radium itself. Considering the great difficulty, experimentally, of the determination carried out by Debierne, the agreement between theory and experiment must be considered extremely satisfactory. near zero ISOLATION OF RADIUM. Another contribution published in course of the year by Debierne, together with Madame Curie, consisted in the isolation of radium itself, for the first time, in the metallic state. A solution of one-tenth of one gram of pure radium chloride was electrolyzed, with ten grams of metallic mercury as the cathode. The radium thus produced formed an amalgam with the mercury. The amalgam was transferred to a small iron boat, placed in a tube of quartz, and subjected to distillation, after the air had been completely pumped out of the tube. As the mercury distilled out, the temperature was allowed to rise higher and higher. The mercury was gone below 700° C., and pure radium remained behind. It formed a shining white residue in the boat, melted at 700° C, was rapidly altered by air, energetically attacked water, forming a soluble oxide of radium, and having altogether the radio-active properties that it was expected to possess. DIRECT DETERMINATIONS OF OSMOTIC PRESSURE were continued during the year in several laboratories. To recapitulate briefly the main facts through the membrane into the solution and render the latter more and more dilute. The force which thus drives the water into the solution has been named "osmotic pressure." A membrane like the one just described is called a semi-permeable membrane." Many animal and plant membranes are semi-permeable, whence the important role played by osmotic phenomena in life processes. About forty-five years ago Traube found that an artificial semipermeable membrane could be made from copper ferrocyanide. Measurements of osmotic pressure were first carried out by Pfeffer in 1877. About ten years later van't Hoff discovered the relationships of osmotic pressure and described them in a remarkable paper, which constitutes one of his chief titles to fame. The van't Hoff theory permits of calculating the osmotic pressure corresponding to a solution of given strength. It further shows that osmotic pressure depends only upon the nature and concentration of the dissolved substance, but is independent of the membrane that happens to be employed: with an ordinary membrane of copper ferrocyanide one ought, according to the theory, to find exactly the same osmotic pressure as by using a membrane made, for instance, of hog's bladder. The finest experimental work in connection with this theory has been carried on for a number of years by Professor Morse and his students at Johns Hopkins University, and the results are in excellent agreement with the van't Hoff theory. Another investigation, which has likewise lasted now for several years and is not yet completed, has been carried on at the University of Wisconsin by Professor Kahlenberg and his students. Instead of using water as a solvent, as did Pfeffer, and as Morse is still doing, the Wisconsin experimenters used pyridine, and in this they dissolved such substances as common sugar, as well as inorganic salts. Their semi-permeable membrane was made of rubber. Working under these conditions about five years ago, Kahlenberg found an osmotic pressure very much smaller than the one required by the van't Hoff theory. In fact, the observed osmotic pressure was only a small fraction of the theoretical. From this Kahlenberg boldly drew the conclusion that the celebrated van't Hoff theory is all wrong, or nearly so, that osmotic pressure is not proportional to the concentration of the dissolved substances, and that it does depend upon the nature of the membrane employed. In the summer of 1910 appeared a paper by Wilcox, a student of Professor Kahlenberg's describing a new series of experiments carried out, apparently, with great care. Wilcox's measurements seem to corroborate Kahlenberg's older work: Wilcox, too, found pressures that were but insignificant fractions of what he should have found in accordance with the van't Hoff theory. Considering this whole matter without any preconceived ideas in mind whatever, one would have at least to doubt from now the validity of the van't Hoff theory; one would be almost inclined to reject it outright. If, however, one investigates the theory with due care, one finds that on it is based on practically nothing else than the The possibility of applying ultra-violet light law of the conservation of energy. The accept to immediate use is pointed out by a communiance of the experimental data of Kahlenberg cation made to the French Academy by Victor and his associates involves not merely rejec- Henri and two collaborators, Helbronner and tion of a theory of the flow of water through Recklinghausen. Henri has for some time been membranes, with which one might dispense studying the action of ultra-violet light upon with no more than a sigh, but a veritable revolu- various micro-organisms. The action appeared tion in physics and chemistry, the rejection of the broadest and most fundamental principle of science the law of the conservation of energy. With preconceived ideas of this nature in mind, one cannot help siding with the van't Hoff theory and against the Kalenberg facts until many more years of the most painstaking experimentation might demonstrate that the Kahlenberg observations are really faultless truth. ULTRA-VIOLET LIGHT. To turn to another subject of reseaarch, recent years have been gradually bringing into prominence investigation of the chemical and physico-chemical effects of ultra-violet light. As time goes on, these effects will undoubtedly form an important chap ter of chemical science. By way of an example of contributions along this line may be mentioned a paper by Svedberg. With the aid of ultra-violet rays from a quartz mercury lamp, Svedberg succeeded in producing colloidal solutions of metals. The surface of the metals is simply cleaned free from oxide and covered with a solvent. A few minutes' exposure suffices to produce the desired effect in the case of lead, tin, copper and silver, and in such liquids as water, alcohol, acetone, and other organic solvents. to be in almost all cases a powerfully destructive one and so the possibility suggested itself of utilizing ultra-violet light for the purification of water on a large scale. The experiments published in the course of the year by the three French investigators were altogether promising, Water containing large numbers of germs and colon bacilli (between 30 and 800 germs per cubic centimetre and from 50 to 100 colon bacilli per litre) was roughly filtered for the purpose of rendering it clearer and hence more accessible to the action of light; then it was caused to circulate through a special apparatus in which it was exposed to the light from a Cooper-Hewitt mercury lamp of quartz. The water was allowed to run rapidly, 25,000 litres passing through the apparatus per hour. The emerging water was absolutely free from colon bacilli and practically free from germs. STEREO-CHEMISTRY. An interesting contribution to stereo-chemistry was published by Perkin, Pope, and Wallach. Organic stereo-chemistry was originally founded by van't Hoff upon the doctrine of the asymmetric carbon atom. An " asymmetric" carbon atom is defined as a carbon atom linked to four other atoms, or four groups of atoms, different from one another. According to stereo-chemical theory, a compound Another series of experiments on the chemical containing one or more asymmetric carbon atoms effects of ultra-violet light was carried out by must rotate the plane of polarized light, and Thiele at the technological institute of Dres- conversely, every compound that rotates the den, Germany. The following are a few of the plane of polarized light must be expected to results: First, the combination of hydrogen and contain one or more asymmetric carbon atoms. oxygen was investigated at the ordinary tem- It has been realized for some time that this perature. Ordinarily, the two gases refuse to principle is not strictly true, that the necessary combine with any appreciable velocity unless and sufficient condition for the optical activity they are heated. When perfectly dry, they re- of a compound is that its molecule, considered as fuse to combine even at high temperatures. The a geometrical body, shall be unsymmetrical, and presence of a trace of moisture greatly catalyzes, that the presence of an asymmetric carbon atom, that is, hastens the reaction. When, however, a while generally an indication of molecular asymmixture of the two elements is exposed at the metry, is not a necessary condition of it. Exordinary temperature to the action of ultra- perimentally, however, no clearly defined case violet light, the two combine readily into water. was known of a compound rotating the plane of Curiously enough, under these circumstances polarized light and yet having an asymmetric the presence of moisture does not hasten, but carbon atom in its molecular. During the year, slows up the reaction. Evidently, the mechan- Perkin, Pope, and Wallach succeeded in preparism of the reaction in the presence and in the ing such a compound-a contribution which absence of ultra-violet light is entirely different. was greeted with pleasure by all those interested Another case investigated by Thiele was the ac- in the working of the atomic and molecular tion of oxygen upon hydrochloric acid. In the theory. The compound in question is termed, absence of ultra-violet light no action can be in the more recent system of nomenclature, 1detected unless an appropriate chemical catalyzer methyl-cyclohexylidene-4-acetic acid. In the is added. In the presence of ultra-violet light older nomenclature, which may be more intellithe hydrochloric acid is rapidly oxidized to gible to some people, it might be called parawater and free chlorine. Similarly, aqueous methyl-pentahydro-phenyl-actic acid. Its forhydrobromic acid exposed to ultra-violet light mula is CH, CH: CHCO2H. As first prein the presence of air rapidly turns brown, pared from optically inactive compounds, the owing to separation of free bromine. Hydrogen substance was, of course, optically inactive. peroxide is decomposed by ultra-violet light with With the aid, however, of the hydrochloride of great rapidity. When a solution of the white the alkaloid brucine, the investigators succeeded of a hen's egg was exposed to ultra-violet light, in breaking up the substance into two componit soon turned yellow and began to smell like ents of equal and opposite rotation. In their scorched nitrogenous matter. The extent of the paper they justly call attention to the fact that importance of such researches will be clear if the new compound furnishes independent proof one bears in mind the grat rôle played in the of the high reliability of the structual formulæ economy of nature by the chemical action of of organic chemistry as atomic pictures of the sunlight, which contains, of course, a consider- compounds represented by them. able proportion of ultra-violet rays. Another line of research, of no small import CHEMISTRY 149 CHEMISTRY 66 ance to organic stereo-chemistry, but unfortu- edge? To return to the question of the color of nately fruitless as yet, has consisted in attempts dyestuffs, a theory which was widely accepted to prepare substances rotating the plane of for a number of years was Witt's so-called polarized light from optically inactive materials " chromophore theory." According to this, color with the aid of circularly polarized light. The is caused by the presence of “ chromophores," problem is a fascinating one in itself and has, that is, of certain atomic groups, such as the besides, important biological bearings. Just as carbonyl, nitro, nitroso, and azo groups, and esin biology it is now accepted as a general prin- pecially of double bonds. Another theory in ciple that there is no such thing as spontaneous vogue is the quinone theory, which considers a generation, that all life comes from other life quinone-like union of atoms essential for color that has existed before it, so it is accepted as a production. Both of these theories have been fundamental principle of stereo-chemistry that of the greatest value in the synthesis of dyean optically active substance can only be derived stuffs but neither can be said to define clearly from another optically active substance or, as the actual cause of color, and recent investigait may be stated, that the spontaneous genera- tions have shown both to be decidedly insuffition of optically active substances is an impos- cient. So we find in the current literature of sibility. Now, the body of all animals and chemical research a considerable number of conplants, chemically considered, is full of optic- tributions attempting to develop a more adeally active substances. For instance, the vari- quate theory. In the front rank of workers ous sugars, starches, celluloses, and albumens along this line we find Professor Hantzsch and are all optically active. While, then, the his students, at the University of Leipzig. bioligist is asking how the first life originated Hantzsch believes that color is due, not to the on our planet, the chemist raises the parallel presence of some chromophore group of atoms, question as to how the first optically active sub- but to the presence of a pair of groups of no stance had come into existence. The only hy- great chemical stability, with a hydrogen atom pothesis that the biologist has as yet been able to capable of migrating from one to the other advance in answer to his question is that the and back, and thus changing the composition first life germs have come here from other and structure of either group. Since the chemworlds. In answer to the parallel chemical ical change thus involved consists only in a requestion, it has been suggested that an optically arrangement of atoms, unaccompanied by a active substance may be formed from an inactive change in the composition of the submaterial under the influence of circularly polar- stance as a whole, the two resulting subized light, that is, ordinary light all of whose stances are obviously isomeric. Furthermore, rectilinear vibrations have been changed into since the change is readily reversible, the subcircular vibrations, with the circular motion be- stance may be considered as tautomeric." Of ing, furthermore, all in the same direction. this tautomeric pair, one substance is colorless, Such light has been known to appear at times the other is colored, and either readily passes in nature, hence, if the chemists should succeed into the other. Plainly, Hantzsch's theory conin artificially producing an optically active sub- tains in it no essentially new concept: it is stance by means of such light, the mystery of merely a modification, a refinement of Witt's the origin of active substances on earth would chromophore theory. But this does not make it disappear. No wonder that in spite of repeated less valuable. Hantzsch calls the colorless subfailures new attempts are made every year in stance and colored isomer "chromo-isomers"; this direction. During the year, Padua, working their mutual transformation or, more preat the University of Bologna, in Italy, examined cisely, the transformation of the colorless into the a priori promising case of the action of the colored form he terms "chromotropy." A bromine upon angelic acid. The latter sub- direct confirmation of Hantzsch's theory was stance is itself optically inactive. The dibromo- obtained by Hantzsch and Gorke in the case of tiglic acid resulting from the action of bromine ortho-nitro-phenol: this substance yields upon angelic acid would undoubtedly rotate the methyl derivative (ester) that is colored. What plane of polarized light if it were produced in is the cause of the color? According to Witt's the body of some animal or plant. But when theory, the color is due to the presence of the Padoa prepared it artificially in a stream of nitro-group. According to Hantzsch, theoreticcircularly polarized light, it was absolutely in ally, there ought to be two tautomeric methyl active, one might say optically dead": one derivatives-one colored, the other colorless. As more unsuccessful attempt. a matter of fact, Hantzsch and Gorke succeeded in actually isolating two methyl esters of orthonitro-phenol, one colorless and the other red. Following in Hantzsch's steps, Willstätter also discovered a pair of tautomeric ortho-benzoquinones, of which one is colorless and comparatively unstable, the other is colored and stable. In certain cases both chromo-isomers may be colored. A mixture of the two in different proportions ought then to yield substances of all possible shades of color, varying from the pure color of the one isomer to that of the other. In accordance with this inference from Hantzsch's theory, certain alpha-oximinoketones, such as di-methyl and di-phenyl violuric acids, are capable of yielding salts of every imaginable color. To this phenomenon Hantzsch applied the name pantochromism." The relative proportions of the two chromo-isomers coexisting and holding balance to each other must 66 COLOR OF DYE STUFFS. A problem of very great importance in organic chemistry is to ascertain the cause of color of dye stuffs. To the chemist this problem means, to ascertain just what composition and molecular structure are necessary and sufficient to produce color. From a practical view-point, this problem solved, the chemist could produce innumerable dyestuffs as yet undreamt of, possessing perhaps any desired hue or shade, and including many of high industrial value. From a purely scientific viewpoint the solution of such a problem, interesting as it is in itself, may quite possibly lead to the unveiling of altogether new treasures of knowledge, as yet completely hidden from view. For did not the hunting up of a peculiar photographic property of pitchblende by Monsieur and Madame Curie lead to the creation of one of the most marvelous branches of human knowl 66 a be expected to vary from solvent to solvent. As a matter of fact, Hantzsch's pantochromic salts yield differently colored solutions in different solvents. This fact might be accounted for on two different principles: first, it might be due, in accordance with Hantzsch's theory, to different arrangements of the atoms within the separate molecules, the outward difference resulting from different proportions of the two kinds of molecules present, but, on the other hand, it might also possibly be due to different combinations of molecules of one and the same kind among themselves. In other words, according to Hantzsch's assumption, the cause is intra-molecular; according to the alternative as sumption, the cause is extra-molecular or, more precisely, inter-molecular. To decide between the two possible explanations, Hantzsch undertook to investigate experimentally, whether there are at all any poly-molecular complexes in solutions of pantochromic salts. The result was decidedly negative: these solutions contained nothing but simple molecules, and hence the cause of their different appearances can only lie within the molecules themselves. In conclusion, it may be stated that this work of Hantzsch's, together with a variety of observations published by Thiele, Baeyer, Stieglitz, Acree, and others, has in very recent years all but disproved the celebrated Ostwald theory of indicators, which was widely and confidently taught but a short time ago, and in accordance with which the color, for instance, of phenol-phthlein in alkaline solution is due to the phenol-phthlein ion being red, while the undissociated substance happens to be nearly colorless. No account of recent work on the connection between the color and constitution of organic substances would be complete without at least some mention of the views and contributions of Baly, Stewart, and Desch. Investigators of this school go a step further than those of Hantzsch's. They believe that color is due, not to some chromotropic isomer of a substance containing a chromophore group, but to the chemical action involved in the incessant mutual transformation of the two isomers. Such transformation may involve, as already indicated above, the migration of a hydrogen atom from one group to the other and back, constituting the phenomenon of tautomerism proper. In certain cases, however, it may only involve the oscilla tion of a valency, in which cases Baly would call the phenomenon isorropesis." Examples of such cases are presented by di-acetyl and by quinone itself. Now, whether a given case be one of true tautormerism, or one of isorropesis, color, according to the Baly-Stewart school, is due to the rapid oscillatory motions going on within the molecule and immediately causing the absorption of light of certain wave-lengths. Any attempt at a critical estimate of the relative merit of the views of the different schools would be out of place in a brief account, especially in the present raw and unfinished state of the investigations. It must, however, be said that the views of the English school seem to possess an unusually promising penetration and illuminating power. 66 Among the contributions published during the year must, finally, be mentioned a series of papers presented in September, 1909, at the 20th Anniversary Celebration of Clark University in Worcester, Mass., by a number of leading American investigators. Practically all American chemical research laboratories were represented at the Clark conference, and each investigator presented a summary of his researches. The papers were gradually published in the course of 1910 in the Journal of the American Chemical Society. The complete set will also appear in the form of a separate Celebration volume early in 1911 and will form a first-hand history of the chemical research carried on in America in our own days. Looking over the splendid material of this volume, one cannot help feeling the truth of Ostwald's prophecy, that the centre of gravity of science is bound to move from Europe across the Atlantic and introduce a new and remarkable era in American history. See ATOMIC WEIGHTS. CHEMISTRY, INDUSTRIAL. The progress in the development of industrial chemistry persists with unabating zeal, and the records of recent years are fully equalled by that of 1910. In two important subjects has there been considerable activity. Improved methods for the extraction of radium, affording greater opportunities for the use of this element; and the synthesis of rubber, the natural sources of which seem inadequate to the demand, are the important features of the progress of the year. ORGANIZATION. The American Chemical Society, now the largest Chemical Society in the world with a membership of over 5100, held two general meetings during the year. The first was in San Francisco, Cal., during July 12-15, and the second in Minneapolis, Minn., during December 28-31. Its president is Wilder D. Bancroft, of Cornell University. The Perkin medal was given to E. G. Acheson of Niagara Falls in recognition of his invention of carborundum, siloxicon, etc. A Willard Gibbs gold medal has been established by William A. Converse for the best paper or address presented before the Chicago section, and is to be awarded annually The American Institute of Chemical Engineers held two meetings during the year, one at Niagara Falls, Ontario, during June 22-24, and the other, the annual meeting, in New York City during December 7-10. Its president is Charles F. McKenna. On the retirement of Prof. Charles F. Chandler from the chair of chemistry in Columbia University his students presented to the trustees of the University in his honor a fund to be known as "The Charles F. Chandler Foundation," the interest of which is to be devoted each year to defraying the expenses of one or more great public lectures on chemistry or some of its applications. The 29th annual meeting of the Society of Chemical Industry of Great Britain was held in Glasgow on July 6-8. On this occasion the Society's medal was presented to Thomas Tyrer for his services to industrial chemistry. METALS. The decay of tin hitherto observed is now further described as catching." A consignment of tin sent from Rotterdam to Moscow in 1877 arrived at the latter place in the form of powder. This alteration is said to be due to a change in the internal crystalline structure of the metal, and may be described as analagous to the slow transformation of monoclinic sulphur to rhombic sulphur. This seems to explain why articles of tin of archeological interest are so seldom found. Cohen described a rare form of tin disease which may be called "strain disease and which may be caused by shocks, compression, or any strain to which the metal may be subjected. Conversion into this state is ac CHEMISTRY celerated by contact with metal that is already in this condition, while melting reconverts it into the normal state. Among the newer uses to which aluminum is being put is its adoption for minor coins. This has been frequently recommended in the past, but it has remained for France actually to replace the bronze 25, 10 and 5 centimes pieces with new coins made of aluminum. In discussing the use of this metal for coinage, the French authorities took into consideration the cost, malleability, weight, and durability of the white metal and agreed that aluminum fulfilled the requirements most satisfactorily. Newer uses for other metals are constantly being found. Tantalum is now being employed in the manufacture of dental instruments, and it is reported from Germany that not only are such instruments cheaper, but they do not rust when exposed to the air, also they retain their polished surfaces longer and are more lasting than steel instruments. The monazite sands from Brazil and from South Carolina are now sent to Germany where they are largely used to manufacture thorium nitrate, a substance employed in the making of incandescent gas mantles. Tungsten ores from Spain are meeting with greater demand, and deposits of wolframite that had been abandoned are now being worked again. The output goes to Germany where the ores are smelted and the metal finds use for making high speed tool steel, also for motor cars, and in the manufacture of electric lamps. The supply of the mines in Argentina is also shipped to Germany. The demand for tungsten for incandescent lamps has resulted in the production of ductile tungsten which is described as a bright, tough, steel-colored metal which can be drawn into the finest wire, much below 0.001 inch. The tensile strength of the wire increases as the drawing proceeds, that is the more the metal is mechanically worked the tougher it gets. Similar results have been obtained with molybdenum, a metal for which, however, the commercial demand has thus far been but slight. 151 IRON AND STEEL. It is reported from Pittsburg that in the mills at Homestead by a process recently discovered the ore dust is to be made into briquettes and utilized in making pig iron. It is claimed its use will effect a reduction in the cost of pig iron. The dust, under the tremendous pressure of the blast, is caught at the top of the furnace, and then carried to the base of the stack, to be carted away. The demolition of a skyscraper " in New York City during the summer months led to the critical examination by an expert of the condition of the steel. He found the steel generally to be in a good state of preservation, although some rivets were corroded. The paint used to "preserve "the steel, made of pure linseed oil, had entirely disappeared, owing to chemical action with the mortar. The main feature of the preservation of the steel was the fact that the columns were encased in brick and a rich mortar or grout came in contact with the metal. Wherever there was insufficient contact between the grout and the steel, rust formed; but as the construction of the building was such that moisture was very largely excluded, there were only two or three instances where bad rust pitting took place. The great lesson to be learned from the examination of this steel is the fact that cement mortar one inch thick around a column CHEMISTRY of steel is the best preservative. Linseed-oil paint should not be used, for there are alkaliproof paints which at the same time electrically insulate and serve a better purpose. A nonrusting iron called "ingot iron" is now a commercial product. It is described as an iron made as nearly pure as possible. Chemical analysis shows it to contain sulphur, 0.005 per cent., phosphorus, 0.005 per cent., carbon, 0.021 per cent., and manganese and silicon, a trace. It is recommended for use in ground where it may be attacked by dampness, in localities where it becomes the intermittent conductor of electrical currents, at the seashore where it is attacked by salt air, or in cities where the atmosphere is impregnated by fumes of gas and coal smoke. A new rust-proofing process for iron and steel is announced in England. The article is boiled in 1 gallon of water to which is added 4 ounces of phosphoric acid, and 1 ounce of iron filings. A black non-corroding coating is produced. 66 ALLOYS. Among the new alloys reported is one to which the name Clarus is given. It is made commercially in Birmingham, England. Clarus is made of aluminum and it is claimed for it that it is at least 60 per cent. stronger than ordinary aluminum and that its weight is one-third that of brass; that it will take a very high polish, equal to that which can be obtained with silver; that atmospheric surroundings do not cause it to tarnish; that castings are not brittle, but can be bent cold; that it is suitable for castings of any size, and that in all circumstances such castings have been found to be sound and free from blowholes and other defects. The new alloy is said to be suited for automobiles and for electric railroad, railroad car, and aëroplane fittings. Also from Birmingham is "Duralium," which is said to be slightly heavier than aluminum and as strong as steel, so that it can be rolled, drawn, stamped, extended, or forged at suitable temperatures; and it is less corrosive than other high aluminum alloys under the usual corrosion tests. It is expected that duralium will find a demand for aviation uses, and in the construction of motor cars, owing to the difficulty of securing aluminum castings sufficiently reliable not to break under the strain of sudden jars and shocks caused by quick stoppages, changes of speed, and jolts upon bad roads. From Germany comes "Ruebel bronze," an alloy, the main ingredient of which is magnesium. This metal in its pure state is unfit for metallurgical purposes, as it is soft and susceptible to atmospheric and chemical influences. Magnesium loses these properties if only small quantities of other metals are added to it. Zinc, copper, and aluminum are added in this new invention in varying quantities, resulting in a fine-grained, homogeneous alloy of considerable strength and low specific gravity. This new alloy is of importance in constructing air ships. The alloy of cobalt and chromium, called "stellite by its inventor, has been described as of value for cutting purposes. Blades made from the alloy take a fine cutting edge, which is particularly smooth, though capable of excellent cutting qualities. A razor made of the cast material had been employed for nearly two years, and had been used for shaving purposes hundreds of times without showing any signs of wear. A lathe tool made from stellite, with |