322 



SCIENCE. 



[Vol. IV.,. No. 86. 



dynamic, and a knowledge of it was more a physical 

 than a chemical problem. From the educational 

 view he thought it better to use the theory of valence 

 in connection with the history of the theories con- 

 cerning atoms and molecules. As a farther step the 

 language and figures of magnetism might be used. 



The paper on the optical methods of estimating 

 sugar in milk, by Dr. H. W. Wiley, showed the great 

 importance which must be attached to the influence 

 of albumen on the specific rotary power of milk- 

 sugar. The author prefers to use an acid solution of 

 mercuric nitrate in precipitating albumen, for an ex- 

 cess fails to dissolve the precipitate. Professor Jen- 

 kins finds, that on adding sulphate of copper and the 

 potassic hydrate the separation of albumen is very 

 complete. 



A discussion on the educational methods in labora- 

 tory practice and in the illustration of chemical lec- 

 tures was opened by Professor Remsen, who remarked 

 that in Germany the student does not go into the 

 laboratory until he understands re-actions, while in 

 England and the United States he is placed there at 

 the beginning of the course. Professor Remsen 

 follows an order of instruction in which the student 

 first becomes acquainted with apparatus and methods 

 of manipulation. He next makes gases, and repeats 

 lecture experiments. He then experiments on oxida- 

 tion and reduction. Next follows the quantitative 

 analysis of air. Then come alkilimetry and acidim- 

 etry, with success. This practical work and the 

 lectures occur simultaneously, and by the time the 

 lecturer has reached the metallic elements the stu- 

 dents are ready to take up test-tube re-actions with 

 profit. During the first year the student should only 

 just begin analysis. After the general properties of 

 the metals are known, let the student devise methods 

 of separation. The course of instruction in our 

 colleges, Professor Remsen regards as too short, and 

 superficial. Lecture-experiments should never be 

 made for show. Aesthetics and chemistry are entire- 

 ly distinct. Professor Atwater said that chemistry is 

 taught now, as a rule, after the student has acquired 



plasm. After a discussion upon fermentation, a 

 motion was carried that a committee of the section 

 should petition Congress to afford facilities for the 

 study of fermentation. Dr. Springer, Professor 

 Wiley, Mr. Clifford Richardson, Professor Remsen,. 

 and Professor Clarke constitute this committee. 



Professor Dewar of the Royal institution read a 

 paper on the density of solid carbonic acid. The 

 solid acid was obtained by compressing carbonic acid 

 snow by a hydraulic press. The specific gravity was 

 found to be from 1.58 to 1.60 of the solid acid. Some 

 little discussion resulted, by which it was brought out 

 that the curves obtained from a study of the critical 

 points of gases may explain some facts in regard to 

 dissociation, as there are many cases where the theory 

 of dissociation and experiment do not agree. The 

 pressure necessary to produce the solid carbonic acid 

 is about one and a half tons. 



Professor Munroe described some experiments 

 which tended toward the establishing of a law of 

 deliquescence. The temperature and shape of the 

 vessel were not taken into account. 



The composition of human milk, by Prof. A. R. 

 Leeds, was found, on using every precaution, to her 

 albuminoids varying from .5 to 4.25 per cent, lactose 

 from 4.1 to 7.8 per cent, and the fat from 1.7 to 7.6 

 per cent. The appearance and specific gravity of the 

 milk never indicated its composition. Improvements 

 in apparatus for rapid gas analysis by Dr. Arthur H. 

 Elliott consisted in reducing the length of the tubes- 

 by enlarging the upper portion of them into bulbs, 

 and in substituting a solution of bromine in potassic 

 bromide for the liquid element to absorb illuminants. 

 Mr. A. H. Allen, in his communication on oils, said 

 that shark and fish oils are often unsaponifiable, and 

 hence are not fatty ethers. He believes them to con- 

 tain cholesterine ,like cod-liver oil. The fixed oils can 

 be separated into groups, but we know no process 

 for separating a mixture of lard and cotton-seed oil. 



These communications closed the sessions of by far 

 the most successful meeting of section C for many 

 years. 



to observe facts. Chemists must show that their 

 science will give what is called 'liberal culture,' or it 

 will not find a place in our educational institutions. 

 Present methods are not doing this, as they fail to 

 make the student think for himself. 



Prof. W. O. Atwater read a paper on the assimila- 

 tion of atmospheric nitrogen by plants. Experiments 

 were made on pease grown in washed sea-sand, sup- 

 plied with proper nutritive solutions. The pease 

 acquired from thirty-eight to fifty per cent more 

 nitrogen than they contained originally, and than 

 had been supplied as nutriment. The above result, 

 Professor Langley remarked, is important, as it is 

 contrary to generally received ideas. 



Dr. Springer next read a paper on fermentation 

 without combined nitrogen, in which he showed that 

 the ferment found on the stems of tobacco-plants, 

 and which decomposes nitrates, on being applied to 

 starch and sugar gives rise to butyric acid, and ap- 

 pears to prove that we can have life without proto- 



PROCEEDINGS OF THE SECTION OF 

 MECHANICAL SCIENCE. 



Owing to previous unfavorable conditions, this was 

 practically the first meeting of the new section (D) of 

 mechanical science. Notwithstanding the great heat,, 

 the small and inconvenient auditorium, and the fact 

 that the electrical exhibition deprived the section of 

 much local support, the meeting was a greater suc- 

 cess than had been expected, and warrants the antici- 

 pation that this will shortly become one of the leading 

 sections of the association as it is in the British 

 association. The attendance was large, and includ- 

 ed many prominent English visitors, who furnished 

 papers, and took part in the discussions. In order to 

 indicate more definitely the scope of the section, it 

 has been proposed to extend its title to ' mechanical 

 science and engineering;' and it is hoped that our 

 leading engineers and architects will give it their 

 active support by presenting before it papers embody- 



