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NOTES AND CORRESPONDENCE Calendar of Meetings American Institute of Chemical Engineers-Pittsburgh, Pa., December 3 to 6, 1924. American Association of Textile Chemists and Colorists-Philadelphia, Pa., December 5 and 6, 1924. American Water Works Association-Wheeling, W. Va., December 5 and 6, 1924. American Petroleum Institute-Fort Worth, Texas, December 9 t o l l , 1924, Third Pan-American Scientific Congress-Lima, Peru, December 20, 1924. American Association for the Advancement of Science-Washington, D. C., December 29, 1924 to January 3, 1925. American Chemical Society-69th Meeting, Baltimore, Md., April 6 to 11, 1925. 70th Meeting, Los Angeles, Calif., August 3 to 8, 1925. American Institute of Chemical Engineers and National Chemical Equipment Association-Providence, R. I.,June 22 to 27, 1925. National Exposition of Chemical Industries-New York, N. Y., September 28 t o October 3, 1925.
The closing remarks of Dr. Palmer indicate that the worst that can be leveled against the Alexander-Schryver view is the Scotch verdict of “not proven.” No doubt there is much work still to be done to clear up what he calls “chemical and physico-chemical changes not yet clearly understood;” but it does add to our knowledge to point out that the extensively operating and potent factor of colloidal protection is a factor to be considered in both the acid and the rennin coagulation of milk. JEROME
ALEXANDER
60 EAST41% S T . NEWYORK,N. Y. October 7, 1924
Determination of Phosphorus in Phosphor Bronze Editor of Industrial and Engineerilzg Chemistry:
Referring to Lindemann’s method for determining phosphorus in phosphor bronze published in THISJOURNAL, 16, 916 (1924), I wish to say that the method has been in use in The Detroit Testing Laboratory for the last fifteen years. It is a rapid and accurate method for certain alloys, such as phosphor bronzes containing over 0.10 per cent of phosphorus. This method is not applicable, however, to any alloys containing less than this percentage, for the amount of acid it is necessary to add in order to Editor of Industrial and Engineering Chemistry: keep the tin from precipitating is sufficient to hinder the comReferring to the correspondence relative to the rennin coagu- plete precipitation of the phosphomolybdate. lation of milk [THIS JOURNAL, 16, 974 (1924)], I would reply The following method, which has been in use in this laboratory thus to the several arguments, questions, and quandaries of Dr. for the last six years, is applicable not only to phosphor bronze alPalmer : loys, but also to brasses containing small amounts of phosphorus. The fact that “perfectly stable suspensions of calcium caseinate It is simple, fairly rapid, and the results obtained by it check can be prepared without the presence of other protective colloids” very closely with those obtained by standard methods. does not show that protective colloids do not protect. By takPlace 2 grams of the alloy with approximately 0.2 gram of ing proper precautions, colloidal gold sols can be made without phosphor free iron wire in a beaker. Dissolve in a mixture of protective colloids, though under a much wider range of con- 30 cc. concentrated hydrochloric acid and 5 cc. concentrated nitric acid. Evaporate to dryness, redissolve with 5 cc. concenditions with them. “The mechanism by which the colloidal dispersion protects trated hydrochloric acid and 100 cc. water. Transfer to a 500-cc. volumetric flask, and pass a rapid current of hydrogen sulfide 15, 283 (1923), and in through it until the sulfides are completely precipitated. Now itself” is described in THISJOURNAL, “Colloid Chemistry” by Alexander (1924). Examples are make up to 500 cc. with water. Shake well and filter through a hand-folded filter paper into a 250-cc. volumetric flask. The sodium oleate, ammonium salts, dibenzoyl-1-cystine (Gortner and Hoffmann), 5-dimethylaminoanilino-3,4-diphenylcydo-l,2-portion remaining in the 500-cc. volumetric flask can be discarded. Transfer the 250-cc. portion (equivalent to 1 gram) into a 400-cc. dione (Hardy), and probably myelins. beaker. Boil off the hydrogen sulfide; oxidize with 15 cc. of Taking up .the numbered points: 3 per cent hydrogen peroxide and precipitate ferric phosphate by adding a slight excess of ammonia. Bring it to a boil, (1) The experiments of Clark quoted “reduce the casein con- filter, and wash the precipitate a few times with water. Redistent t o 0.2-0.3 per cent, while mothers’ milk has about 1.26 per solve the precipitate in a flask with hot 50 per cent hydrochloric cent. As von Weimarn has shown and every analyst knows” acid. Make it ammoniacal, and acidify with 50 per cent nitric dilution in itself will reduce the size of the flocculates in a pre- acid, adding a few drops in excess. Bring the solution to the cipitate. proper temperature and precipitate phosphorus by the addition (2) Will the “perfectly stable suspensions of calcium casei- of 50 to 60 cc. of the regular molybdate solution. nate” be stable in the presence of the percentages of salts, lacFrom this point on, the phosphorus determination is carried’ tose and other solutes found in milk? Unless this is provedout in the usual manner. and it seems improbable-the suspensions cannot be termed With a little experience it is possible to complete a determina“perfectly stable.” (3) Because of the principle of cumulative protection (see tion of pbosphorus by this method in less than 2 hours. foregoing references), the quick action of rennin is compreHENRYJ. JAMESON hensible. Gelatin and gum arabic protect against rennin 564 BAGLEY AVE. coagulation. DETROIT, MICH. (4) Mothers the world over use and have been using protecSeptember 5, 1924 tors to protect cows’ milk-gum, gelatin, barley gruel (plain or dextrinized), seaweed (Irish moss), dark beer (in Bavaria), citrate ........... (especially in England)-substances which have nothing in common except that they actually do protect. I would suggest Editor of Industrial and Engineering Chemistry: that Dr. Palmer try the coagulation of cows’ milk in the presence Referring to Mr. Jameson’s strict limit of a minimum of 0.10 of gum arabic, using rennin, which should not affect the gum or per cent of phosphorus, I beg to draw your attention to the fact its protective action. ’
The Rennin Coagulation of Milk
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December, 1921
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and make as much as a kilogram of some of the organic resinate and fatty acid metallic soaps. There were twenty-one students in my class, exceptionally bright and keen, and all with an intense desire to learn. I lectured from nine to ten, and from ten to eleven was devoted to asking questions. Classes were, of course, conducted in English, but whenever Professor Dage felt that some of the students did not quite understand, he translated what I said into Chinese. After tiffin (lunch) we had laboratory work from two until five o’clock. Saturdays and Sundays were devoted either to sightseeing or to delivering popular lectures a t other institutions. During my stay in Peking I delivered twenty college lectures and five public lectures. My trip to Hankow was most interesting. Here I visited the so-called wood-oil refineries and learned more there in four days than I ,had accumulated in twenty years. As a matter of fact, I had to unlearn many erroneous traditions about the Chinese. The loyalty of the professors is remarkable. I was reliably informed that the Chinese Government had not paid any salsries for more than six months. Most of these professors are married men, but how they live I do not know, unless it is that they have saved Some money from their previous salary and living in China is exceedingly cheap. I wonder how long an American professor would remain loyal to his institution LEIF LINDEMANN if he had a wife and children to support and did not receive his salary for six months; and yet these men go about their duties as cheerfully and earnestly as if they received big salaries regularly. MAXIMILIAN TOCK
that the reviewer of my article found results by this method of 0.114 per cent phosphorus, using a 1-gram sample of a standard phosphor bronze containing 0.112 per cent phosphorus as standardized by the magnesium pyrophosphate method. The solutions had a value for phosphorus of 1 cc. =k 0.010 per cent phosphorus, using a 2-gram sample of a standard steel. As there may be some inaccuracy with alloys containing less than 0.1 per cent phosphorus, especially in the hands of inexperienced laboratory assistants, I recommend that this be accepted, not as an absolute limit, but as a practical rule. If the phosphomolybdate is precipitated in an amount which is expected to give less than 0.1 per cent phosphorus, 0.100 per cent of phosphorus in the form of a standard solution of phosphoric acid or phosphate may be added. Thus it is possible to enlarge the scope of the method to include small amounts of phosphorus which may be of interest in investigations of the primary crystal limits in malleable special bronzes and brasses. It is also possible to complete both the determination and the check on a synthetical mixture of pure chlorides in each special case in less than two hours. In estimating the value of this method among analytical procedures in the metal industry, one must not be surprised to hear of earlier methods of the same nature. KONGSBGRG, NORWAY October 11, 1924
A Chemistry Professor in China
Editor of Industrial and Engineering Chemistry: My experiences in China as honorary professor of industrial chemistry a t the National Institute of Technology were unique. The train that carried me from Shanghai t o Peking had two steel armored cars, one in front and one in the rear, containing seventy soldiers, several machine guns, and four powerful searchlights which illuminated the road on both sides all night long. In my car two officers, fully armed, were on duty all night. The train itself, called the Blue Steel Express, was built in America and was as comfortahle as any one of our fine trains.
PROFESSOR TOCH A N D HIS CHEMISTRY STUDENTS
The teaching of the industrial sciences in China has only just begun and the National Institute of Technology, which was formerly called The Government Technical College, is a composite of Pratt Institute, Cooper Union, and the Massachusetts Institute of Technology, except that the equipment is very much poorer and more crude, and it is not possible to telephone to a supply house to get what one needs. There is no gas. All ordinary heat reactions are carried out by means of alcohol lamps. Higher temperatures such as I use for the refining of oils and in themakingof driersareobtained by means of most perfect little coke stoves which one sees all over China. In fact, in the laboratory we were able to refine four liters of oil
YORK, x. Y . October 23, 1924
h-EW
Fiftieth Anniversary of Stereochemistry Editor of Industrial and Engineering Chemistry: A celebration in honor of the work of van’t Hoff and Le Bel was held on October 25 in the Senate Chamber of the University of Amsterdam. The meeting was opened by Professor Goester, vice president of the Netherlands Chemical Society. The purposes of the gathering were described and a cordial welcome was extended to the delegates from the chemical societies of England, France, Belgium, Germany, and the United States. Professor Cohen, of Utrecht, then described the personal character of van’t Hoff and Le Bel. He read many interesting extracts from letters written by van’t Hoff. At the close of his discourse he invited those present to rise and by this action join with him in sending a telegram of greeting to M. Le Bel, who on xcount of advanced age was not able to be present. The tele! ‘am was immediately thereafter dispatched by messenger from the hall. Professor Walden, of the University of Rostock, the.. gave an address on stereochemistry in which particular bttention was paid to the advances which have been made in this field. At the close of the exercises tea was served in an adjoining room and an opportunity was afforded to meet, among others, the widow and one of the daughters of Professor van’t Hoff. In the evening an elaborate banquet was given. Among the many interesting talks, that of Prof. Henry E. Armstrong should be mentioned. He pointed out, and showed by means of solid models, that the new studies being made in England on the geometrical configuration of molecules confirm van’t Hoff’s and Le Bel’s conception. He urged more intensive studies along this line. His talk was interspersed with many interesting accounts of his personal acquaintance with van’t Hoff. To an American a t such a gathering as the present one, the facility with which the Hollanders can address everyone present in his own language is a never-ending source of wonder. ATHERTON SEIDBW PARIS, FRANCS
October 27, 1924
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