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material gravimetrically, in another volumetrically; and in the lecture room the student should be taught the application of these methods t o the most varied kinds of industrial products. There is no finer practice than the complete analysis of a rock, but for a student it consumes an immense amount of time. Even if there is not time, however, for the complete analysis, the fundamentals of rock analysis can still be taught, for the student will already have made a partial analysis of limestone, probably a silica by fusion, and a determination of sulfur in some form. In a one-hour lecture this work can be gathered into a n organized whole, and correlated with the subject of a complete rock analysis. The student can then be required to determine ferrous iron, alkalies, titanium, and the other constituents which his previous experience has not covered. Thus by the organization of the laboratory work through the correlating influence of carefully planned lectures and theoretical study, a much broader foundation can be laid in the allotted time than is now usually done. In summarizing, analytical chemistry should be taught as one subject, with the various branches closely correlated in a unified system. An unnecessary burden is placed upon students by using different methods in presenting the fundamental principles of qualitative and quantitative analysis. Much laboratory time can be saved by more lecture work, and by the avoidance of undue repetition in analytical exercises. This time should be spent in extra drill in the details of accuracy. UNIVERSITY OF ARIZONA PAULH. M.-P. BRINTON TUCSON, February 14, 1917
A CHEMICAL LETTER BY DR. ANDREW URE Editor of the Journal of Industrial and Engineering Chemistry: The following letter by Dr. Andrew Ure-the well-known author of Ure’s Dictionary-has recently come into my possession and as it was written exactly 100 years ago and contains considerable matter of historical interest, its publication in the July issue of the JOURNAL may not be out of place. The letter, except for a slight tear due t o breaking of t h e wax seal, is in perfect preservation. It bears the address, Dr. Granville, Hotel de Saxe, No. IZ Rue de Colombier, Faubourg St. Germain, Paris, and runs as follows: GLASGOW, July j t h , 1 8 1 7 MY DEAR SIR: I avail myself with great pleasure of the opportunity offered by the visit of my ingenious friend, Dr. N. Hill, to Paris, to assure you of the grateful recollections which I shall ever entertain of your kindness, regretting only that the arthritic affection of my ankles prevented me from profiting so much as I would otherwise have done of your acquaintance with the French Savans. M y journey homeward was tedious and uncomfortable; but soon after breathing my native Caledonian air my health returned to its former soundness, and the anomalous affections, connected, I believe, with the French wines, entirely disappeared. Though far distant from you, I have followed with undiminished interest your useful labors and very interesting communications in the Institution Journals. Your tribute to Vauquelin is elegantly expressed, and very justly merited. It has found an echo in every man’s heart who has, like me, had the good fortune t o meet with this illustrious and benevolent philosopher. I hope soon t o have a public opportunity of expressing my sentiments on the same grateful subject. M y winter occupations consist more in teaching pupils the general truths of science than in original investigations. Since the session ended, I have, however, been incessantly occupied in some researches which will make their appearance in monthly succession in our scientific journals-chiefly the Annals of Philosophy. I n the Medical and Surgical Journal of London for this month you will find a paper of mine containing a description and analysis of a morbid intestinal concretion sent to me for examination by a physician in the vicinity of Perth. It differs entirely from any of which I have seen a n account, resembling in chemical and physical properties pure ambergris, and containing no earthy phosphates or indeed any other saline matter. By the analysis of Lagrange ambergris contains benzoic acid.
Vol. 9, No. 7
The substance in question yields none to any attempts a t extraction which I have been able to make. And on examining with care two different specimens of ambergris, both reputed genuine, I have found the one to contain benzoic acid, but the other, and that the most characteristic, none. The paper itself will shew YOU that I have bestowed some pains on the subject, though I have by no means completed my investigations, being very much pressed for the account for this month’s magazine. Some phenomena led me t o fancy that the acid of ambergris was not benzoic but succinic acid; and I accordingly tried t o discover a simple and certain criterion between them. Succinate of Ammonia sublimes without decomposition. Benzoate of Ammonia is decomposed in a gentle subliming heat; the Ammonia escaping partly in gas and partly combined with the water of crystallization. This fact, if you please, you may mention to M. Vauquelin; but very likely that excellent chemist may be already acquainted with it. M y first paper for the Annals, is on Ammonia, Muriatic Acid, Sal Ammoniac, the other Ammoniacal Salts, and the chlorides in general. It contains I believe several new facts, which I hope you will see next month. I should wish exceedingly to know the opinion concerning it of your distinguished friends a t Paris. Will you write me? The whole deductions are from my own experiments. I point out some inaccuracies in Dr. Wollaston’s Scale as well as in Dr. Thomson’s Weight of the Atoms. I endeavor to show that Sal Ammoniac is not a chloride of ammonium, as Dr. T. has called it. The bearer of this letter is author of a very ingenious paper on Laryngitis, and very deserving of being assisted in his views of seeing a little of Parisian Practice. As there is no person who is so thoroughly capable of promoting his views, may I beg you t o give him a general system of directions for making the most of his time a t the French Capital? Present my respectful complements to your lady and believe me t o be always, Dear Sir, Your faithful and obliged servant, ANDREWURE Dr. Augustus Bozzi Granville, t o whom the above letter is addressed, had one of the most adventurous careers which ever befell a man of science. He was the son of an Italian named Bozzi, a relative of Napoleon, but afterwards adopted the family name of his English mother. He studied under Volta a t Pavia, from which university he graduated as a physician in 1802. Granville was an enthusiastic devotee of the new science of chemistry. At Paris he became acquianted with Countess Rumford, the widow of Lavoisier, who encouraged him in his chemical studies; Gay-Lussac, Vauquelin, and other well-known chemists were among his teachers. I n 1814and 1815 Granville taught chemistry a t a medical school in London. His experiences, however, as a teacher of chemistry were unfortunate; an accident with chlorine gas completely destroyed his sense of smell and, the treasurer of the school absconding, the institution failed and Granville was never paid his salary. After this he returned to France and was studying in Paris a t the time of Ure’s letter. Granville’s extensive travels, together with his linguistic attainments, gave him a wider acquaintance with noted scientists than was the fortune of most other men of his day. He rendered no small service by helping to bring together English and Continental scientists who had been separated from one another by the Napoleonic wars for nearly 20 years. Granville’ died in 1872 a t the age of 88 and his long life forms a connecting link between the chemists of Lavoisier’s time and those of the present day. Although the imperfections of Ure’s analytical methods throw little light upon the nature of his “morbid intestinal concretion,” it seems probable that he was dealing with cholesterine or coprosterine, substances of which chemists are still striving t o determine the exact constitution. The allusion which Ure makes to his researches upon the composition of sal ammoniac recalls the famous “chloridic controversy” which occupied the minds of chemists a century ago. Ure’s paper was published in Thomson’s Annals of Philosophy 1 Granville was well known as an authority upon mineral waters and sewage disposal. He also made important contributions to the study of the internal use of hydrocyanic acid in medicme. His two-volume autobiography published in 1874 has all the fascinations of an exciting novel.
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for Sept. 1917 (Vol IO, page 203), and in it he contends that salammoniac is not a chloride of ammonium hut a muriate of ammonia. According t o the old view muriatic acid and ammonia both contained oxygen while hydrochloric acid and ammonium were oxygen-free. The muriates upon heating were supposed t o be converted into chlorides by the expulsion of water. Ure sublimed dry sal ammoniac over hot metals and obtaining water concluded that the latter was due t o a combination of the hydrogen and oxygen in the sal ammoniac molecule. Sal ammoniac was therefore a muriate and not a chloride. The fallacy of this conclusion was pointed out by Thomson (in Vol. I Z of his A m a l s , p. 381) who by a natural intuition picked the winning side in the chloridic argument, as he did in the atomic controversy, years before most of his contemporaries. Although Ure in after years realized the correctness of Thomson’s view, he had the satisfaction of knowing that he went astray in good company. Berzelius believed up to 1820 in a hypothetical element muriaticum, which, upon combining with two atoms of oxygen, produced the anhydride of muriatic acid; this anhydride, upon further oxidation, as by means of manganese peroxide, yielded oxy-muriatic acid gas or chlorine Berzelius also believed in another hypothetical element nztricum, the oxide of which was nitrogen and which oxide in combination with hydrogen gave ammonia. Relics of these old views still survive in chemical nomenclature. The contribution of Ure. who was assisted in his experiments by Gmelin, a pupil of Berzelius, will always be worth reading, for it illustrates the difficulties with which early experimenters had to contend. As Kopp remarks in his account of the chloridic controversy, “it is interesting to note how correct observations led t o incorrect conclusions.” The tributes which Granville and Ure both pay to.Vauquelin only confirm what others have written about one of the best loved and most honored chemists of France. The readiness with which English scientists, after the bitter Napoleonic wars, could give expression t o such feelings of admiration shows the strength of the bonds which unite the great international brotherhood of science, and a t the time of the present crisis should fill us with hope for the future. 80 SOUTHSTREET, ~ - E WYORKCITY C. A BROWNS May 16. 1917
TWO LETTERS ON THE INCOMPLETE HYDROGENATION OF COTTONSEED OIL Editor of the Journal of Industrial and Engirieering Chemistry: I n a very interesting article entitled “Incomplete Hydrogenation of Cottonseed Oil,” by Hugh K. Moore, et al., published in the May 1917 number of THISJOURNAL, the following statement occurs on page 461 under the caption “Response to Halphen Test: The amount of hydrogenation which is required to render the oil just incapable of responding to the test has not to our knowledge been investigated.” A very limited amount of experimental data is given and a conclusion is drawn on page 462: “The degree of hydrogenation necessary to destroy the response of Cottonseed Oil to the Halphen test has been shown t o be a drop of about four units in the iodine number.” There are so many variable factors which would have an effect on this conclusion that it seems a rather broad statement to make on the limited evidence submitted. I t is rather interesting to the writer that the statement is made in the article that “the amount of hydrogenation which is required to render the oil just incapable of responding to the test has not to our knowledge been investigated,” in view of United States Patent 1,187,999, application for which was filed by the writer on August 31, 1915, and issued on June 20, 1916, in which the following statement appears in the specification: “ I n carrying out my new process for the manufacture of the
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product, a fatty oil, for instance, choice or prime yellow cottonseed oil, is placed in a closed vessel and caused to be chemically combined with hydrogen in the presence of a catalyzer. Any of the known processes of hydrogenation, or any active catalyzer may be employed, which does not leave any residual catalytic impurities in the product after careful filtration. A temperature of 150 to zoo’ C. has been satisfactorily employed, and the time required to produce the desired result after attaining this temperature, is from five to thirty minutes, depending upon the activity and proportion of the catalyzer employed. I n practice the time or degree of hydrogenation desired are determined by preliminary experiment on the oil and catalyzer used in an experimental apparatus. In carrying on such preliminary test the hydrogenation process is continued until a sample of the oil fails to respond to the Halphen reaction and the desired degree of crystallization takes place when the oil is chilled. “Depending upon the particular oil treated by the process, the iodine value of the finished product varies from about 90 to 102. Its titre (as determined by the Wolfbauer method) has been slightly increased during the process to the extent of from about 0 . I to 0 ,j O C. over that of the original oil treated. The color of the treated product is usually somewhat lighter than the original oil. On cooling the product it in part readily crystallizes, thereby making separation of the stearin from the oil much easier and more effective for ‘winter pressing’ for salad oil than is the case with ordinary cottonseed oil. The new product responds negatively t o the Milliau test for cottonseed oil.” Other parts of the specification and also the claims of this patent treat further on this subject. Inasmuch as a copy of this patent was sent to the Berlin Mills Company and was investigated by their patent attorney, it is somewhat surprising to the writer to find a t this time an article published by the research laboratory of this company over the name of the company, in which the abovequoted statement occurs. ARTHURLOWENSTEIN CHICAGO,June 6 , 1917
......... Editor of the Journal of Industrial and Engineering Chemistry: In reply to Dr. Arthur Lowenstein’s criticism of a section in our article on “The Incomplete Hydrogenation of Cottonseed Oil,” we wish to state that U. S.Patent 1,187,999 was familiar to us a t the time the section in question was written; neither a t that time nor a t the present time, however, could we regard the disclosures of the patent as constituting anticipation of our work. The fundamental statement of the patent, as quoted above by Dr. Lowenstein, is as follows: “ . . . . . . the hydrogenation process is continued until a sample of the oil fails to respond to the Halphen reaction and the desired degree of crystallization takes place when the oil is chilled.” There is no warrant for assuming from the language of the patent that when the Halphen test is just destroyed the proper amount of crystallizable material has just been produced; in fact it would appear that a considerable degree of choice may be exercised in the production of this stearine after the Halphen test response is gone. The iodine number of the product of the patent is not stated to be that of a product in which the response to Halphen test has just been destroyed, but is that of a product in which both conditions have been met. The breadth of the range given, go102, indicates that “the desired degree of crystallization” upon chilling, is subject to considerable variation, according to the object in view. The other distinguishing mark given in the patent, namely, a range of increase in titre, likewise fails to disclose any definite knowledge of the degree of hydrogenation necessary to destroy the response to the test; its indication is ambiguous, like that of the iodine number. We have not experimented with t h e Wolfbauer method, since its use is uncommon in this country, but it is certain that the range of 0 . I to 0.5 C. represents a very
