234 SCIENCE. 



AMERICAN CHEMICAL SOCIETY. 



The regular meeting of the American Chemical So- 

 ciety was held Friday evening, May 6. Vice-President 

 Leeds in the chair. Messrs. J. G. Mattison, Theo. 

 Tonnele, and Dr. Otto Grote were duly elected members, 

 and Messrs. A. H. Van Sinderin and C. P. Sawyer as 

 associate members. Mr. A. P. Hallock was proposed for 

 election. The first paper on the programme was " On a 

 Slight Modification of the Wilkinson Gas Eudiometer," 

 by Mr. James H. Stebbins, Jr., S. B. Having found con- 

 siderable difficulty in the manipulation of the instrument 

 as described by Dr. Wilkinson, Mr. Stebbins succeeded 

 in overcoming his objections by bringing the stopcock 

 nearer to the Eudiometer itself. It is very difficult, in 

 fact impossible, to properly explain the improvement 

 without illustrations. At the conclusion of Mr. Steb- 

 bins' paper, Dr. C. A. Doremus very thoroughly ex- 

 plained the method of procedure used by Dr. Wilkinson 

 in his working of the Eudiomettr. This made the mat- 

 ter clearer, still the improvement by Mr. Stebbins was 

 thought desirable. 



The next paper* was by Dr. T. O'C. Sloane, " Note 

 on the Purification of Baric Sulphate." The authon 

 finds in order to obtain a precipitate of barium sulphate 

 that will not run through the filter, a few rules must be 

 observed. These he gave as follows : ist. The solutiou 

 must be barely acid. This end he secures by using 

 cochineal, finding by its use that the neutralization can 

 be more expeditiously and exactly performed than with 

 litmus. 2d. The precipitant is added when the solution 

 is almost up to a boil and kept at that temperature for 

 some minutes. By following these two suggestions a 

 heavy precipitate with a perfectly clear supernatent 

 liquid will be obtained. In case any iron salts have been 

 carried down with the barium sulphate, the precipitate is 

 to be treated first with hydrochloric acid and secondly 

 with sulphuric acid, but this process is open to some ob- 

 jections. It is therefore best to fuse the precipitate with 

 sodium carbonate and a very little sodium nitrate and 

 redetermine the sulphur. As an improvement, Dr. 

 Sloane finds the following method quick and reliable : 

 The sulphur is precipitated in the conventional manner 

 with the previous mentioned precautions carefully ob- 

 served. The solution is then decanted to the last pos- 

 sible drop through a filter paper ; 5 or 10 c.c. of cone, hy- 

 drochloric acid are then added and the beaker held in the 

 hand over a hot plate until the acid is brought to a full 

 boil. It is allowed to continue so for a few minutes, then 

 cooled and diluted. The liquid neutralized with cochi- 

 neal solution, re-acidified and poured into the filter. By 

 this manner a white and clean precipitate was obtained. 

 Dr. Sloane immediately followed with a description of a 

 new " Qualitative Test for Carbon Disulphide and Carbon 

 Dioxide in Coal Gas." A piece of caustic potash, a few 

 m. m. long, is added to ten or twenty c. c. of alcohol, into 

 which a piece of potassium carbonate has been added. 

 The alcoholic solution of potash is placed in a suitable 

 absorption tube and a cubic foot or more of gas passed 

 through it. It is then removed from the absorption ap- 

 paratus and poured into a test tube. If the gas con- 

 tains any carbon dioxide, an o ly lookirg layer, nearly 

 colorless, of a solution of potassium carbonate will under- 

 lay the alcohol, which latter will have acquired a reddish 

 color. The alcoholic solution, which, if any carbon bi- 

 sulphide be present, will contain potassium xanthate, is 

 boiled and tested for hydrogen sulphide. Another 

 method, is to add an excess of a copper salt, filter out the 

 precipitated copper compounds and pour ammonia 

 through the filter paper, when a highly characteristic 

 yellow precipitate of copper xanthate will remain be- 

 hind. 



The fourth paper was by A. R. Leeds, Ph. D. Its 



* I would acknowledge my indebtedness to Dr. Sloane for his kindness 

 in lending me his original MSS. — M. B. 



title was " Upon the Direct Conversion of the Aromatic 

 Amides into their corresponding Azo-compounds." 



This paper was a sketch of the recent work which Dr. 

 Leeds has been prosecuting in his laboratory at the Ste- 

 ven's Institute. It consisted, as described in the title, of 

 the details incidental to the conversion of the different 

 aromatic amides into the corresponding azo-com- 

 pounds with the peculiarities of each commented on. 

 Many of the hydroxylated compounds were also operated 

 on by Dr. Leeds. 



Mr. A. A. Julien followed with a very interesting paper 

 " On the Chemical Contents of the Fluid Cavities of 

 Minerals." Mr. Julien is the well known lithologist of 

 the School of Mines in this city, and has a higher repu- 

 tation in this specialty than almost any other scientist in 

 this country. 



He first gave a general outline of the history of the 

 subject. It is only comparatively recent that any atten- 

 tion has been paid to these cavities, which are very mi- 

 nute in size and generally of a rounded shape, though 

 sometimes following the outlines of a crystal, that is to 

 say, the cavity is of the same shape as a crystal of the 

 substance in which the cavity occurs. New York is, for 

 many reasons, the best place to study this subject; for in- 

 stance, a greater number of specimens find their way to 

 this city. Among the substances found in these cavities 

 are : water, carbon dioxide, nitrogen, sulphur dioxide, 

 ammonia, fluorine, chlorine, oxygen, hydrogen disulphide, 

 and rarely bituminous and light hydro-carbons. 



Herkimer, N. Y., is a locality where the latter are fre- 

 quently found. 



Carbon dioxide is, however, the most interesting of 

 these substances to the chemist, and it is also the one 

 most frequently met with. It is found in some fifteen 

 localities throughout the United States. One locality is 

 known in New York State. These cavities are generally 

 found in granites, granito-porphyries, hornblendic and 

 other gneisses and in smoky quartz. The most character- 

 istic feature of the carbon dioxide in the cavities is its re- 

 markable expansive quality — so great that in touching it 

 the warmth of the hand will completely vaporize the 

 liquid compound. Mr. Julien has devoted special atten- 

 tion to the determination of the temperature at which 

 the liquid expands and for that purpose has devised a 

 form of apparatus to be used in such estimations. The 

 piece of mineral containing the cavity is mounted on a 

 microscopic slide and placed in the new apparatus, 

 which consists of a long metallic box, with a small tube 

 on the surface, to which a rubber tube is attached. The 

 whole apparatus is placed in the microscope. On blow- 

 ing into the rubber tube sufficient heat is obtained to 

 cause the expansion of the bubble of carbon dioxide. 

 Readings are made of the temperature at which the bub- 

 ble disappears and also of the temperature at which the 

 bubble reappears. Mr. Julien's results agree within two 

 tenths of a degree Fahrenheit. 



Thus by the ordinary method (Fuessi's) two results, 

 80.1 and 79.5 were obtained, while with the improve- 

 ment six results were obtained as follows: 79.6, 79.4, 

 79.6, 79.5, 79.5 and 79.6. Mr. Julien also gave a very 

 interesting description of "Reticular Fluid Cavity" in 

 Topaz from Braz'l, whose bubble was the largest ever 

 discovered, being 2.28 m. m. in length. He also referred 

 to the spontaneous motion observed in the bubbles and 

 to the general bearing of the entire subject of the gen- 

 sis and formation of rocks. M. B. 



M. Duchemin, the inventor of the compass with circular 

 magnets, now adopted in the French navy, has lately de- 

 vised, for correction of compasses, a system of magnetic 

 compensators, in which magnetic bars of annular or circu- 

 lar form are used in place of the straight ones. These have 

 the advantage of insuring much greater magnetic stability 

 than straight bars, especially when lightning occurs in the 

 neighborhood of the ship. 



