SCIENCE. 



THE AMERICAN CHEMICAL SOCIETY. 



The April meeting of ihe American Chemical Society 

 was held on the evening of the ist inst. There not be- 

 ing a quorum present at eight o'clock, the business of the 

 Society was postponed, and the reading of Dr. A. R. 

 Leed's paper on " Anilo-metallic Compounds" took 

 place. The aniline compounds of Aluminum, Antimony, 

 Barium, Calcium, Cadmium, Chromium, Copper, Cobalt, 

 Bismuth, Mercury, Tin and Zinc were described ; how 

 they were prepared and their important characteris'ics 

 noted. Aniline will not combine with any monivalent 

 element. This paper was a preliminary report of work 

 which Professor Leeds proposes to extend and ultimately 

 publish when he shall have obtained sufficient data. The I 

 second paper on the " Action of Concentrated Sulphuric 

 Acid on Lead Alloys " was read by Lucius Pitkin, one | 

 of the most talented young chemists of the School ot 

 Mines, N. Y. In a paper presented by Mr James Nap:er j 

 before the Glasgow Philosophical Society, it was held j 

 that impure lead was preferable to the pure article foruse 

 when in contact with sulphuric acid (see Chemical News, I 

 Dec. 23, 1880). Mr. Pitkin tried the action of both hot 

 and cold concentrated acids on some forty samples of lead 

 and its alloys. The alloys treated were of lead with 

 antimony, tin, bismuth, cadmium, silver and zinc. In the 

 case of cold acid, 2 sq. in. of each alloy and a sample of i 

 pure lead were exposed for 24 hours to the action of 10 

 c.c. of sulphuric acid at 20 C; on hot acid the length of 

 exposure was one hour, and his results are best given in 

 the following table, with which his paper terminated. 



Average solubility or liability to formation of sulphate 

 of the alloys in terms of lead. 



Cold Acid. Hot Acid. 

 Lead 1 . 1 . 



" alloyed with Antimony 81 2.75 



" " Tin 1.42 .75 



" " Bismuth 1.10 7 .69 



" " Cadmium 86 1.10 



" " Silver 87 .93 



" " Zinc 1.53 i.io 



Considerable discussion followed Mr. Pitkin's paper, in 

 which Dr. Gallatin, Dr. Geyer, Dr, Alsberg, Mr. Herres- 

 hoff and Dr. Squibb participated. 



Mr. A. E. Hoppick was then elected a regular member 

 of the Society, and Messrs. C. P. Sawyer, A. H. Van 

 Sinderen, and Otto Grote, were proposed for election. 

 Mr. J. H. Stebbins was elected to fill the vacancy caused 

 by the resignation of Dr. Gallatin, as Recording Secre- 

 tary, and Mr. Herreshoff elected to the positien on the j 

 Committee on Nominations which Mr. Stebbins had held. 



Mr. Casamajor and Dr. Alsberg reported on behalf of 

 the Committee for the Annual Dinner, and announced 

 that the fifth anniversary dinner of the American Chem- 

 ical Society would take place at fc'ieghdrtner's restaurant, 1 

 on Monday, April 18, at 6 P. M. M. B. 



ON SOME PHENOMENA PRESENTED BY YOR. ! 

 TEX-RINGS. 



PROFESSOR A. E. DOLBEAR, TUFTS COLLEGE, MASS. 



[. It one vortex-ring strikes another vortex-ring upon i 

 the edge the two rings will bound away from each other 

 as though they were solid elastic bodies, each one vibrat- I 

 ing as it recedes. 



2. If one vortex-ring overtakes another ring, both I 

 moving in the same straight line, and both are of the j 

 same size, then the forward one will expand in diameter, 

 and the latter will contract in diameter, and will go 

 through the forward one when each will return to its 

 original dimension. At the same time the forward one ; 

 will have its velocity retarded while the other will have j 

 its velocity increased, and it may overtake the forward j 

 one and go through it. 



3. If a vortex-ring passes near any light object as, for in- 

 stance, a silk thread suspended, or better still a small 

 cloud of smoke or ammonium chloride dust, the latter 

 will be seen to be apparently repelled from the front of 

 it but attracted and drawn into the ring from the rear. 



4. If a vortex-ring be projected parallel with any sur- 

 face, and at not too great a distance from the surface, 

 the ring will move in a curved path towards it and 

 strike it. 



5. If two vortex-rings are projected so as to start in 

 parallel lines near to each other they will approach each 

 other until they touch, when they may be either broken 

 or else bound away from each other as in the first case 



above. 



6. If two vortex-rings having the same rate of rota- 

 tion be started in lines parallel to each other and at not 

 too great a distance apart, they will not only approach 

 each other but they will combine to form one ring 

 w hich continues to move in the same direction. 



7. The combination is effected by the breaking ot 

 each at the point of contact, and the welding of the 

 opposite parts of each ring to fotm one ring with twice 

 the diameter. 



8. Three rings may in like manner be combined into 



one. 



9. The structure of the vortex-ring is concentric, that 

 is, a cross section of a ring generally shows a series of 

 several concentric circles, with a hollow centre. The 

 middle of the ring appears to be a cylindrical unoccupied 



space. 



As experimental work with such rings is very enter- 

 taining as well as suggestive of the behavior of the real 

 atoms of matter, it may be well to give the simple 

 instructions necessary to perfect success. 



Provide a cubical box with dimensions about a foot 

 each way, having a swinging back frame, over which is 

 stre'ehed a piece of stout cotton cloth. On the opposite 

 side two or more inch-holes may be bored two inches 

 apart. Pour some strong hydrochloric acid into one 

 saucer, and some strong ammonia water into another. 

 Set the two into the box, and shut down the door. The 

 box will at once be filled with the white fumes, and a tap 

 with the finger upon the cloth back, will send out well- 

 formed rings. 



The phenomena 1 to 5, can best be seen by employing 

 only one of the holes, so as to form but a single ring. By 

 striking the cloth a little harder the second time than the 

 first, the second ring may be made to overtake the first, 

 and if it is desirable to exhibit the rings to a room full of 

 people, there should be but a single hole in front, and 

 that one about three inches in diameter; the rings can 

 then be projected with force enough to make them go ten 

 or fifteen feet from the box. 



The other phenomena can best be studied by using 

 only small holes, and tapping gently. The rings will 

 come together within a few inches of the box. It seems 

 to be essential that the two rings that combine, should 

 have the same rate of rotation, a matter easily secured 

 by forming the two at once in the above described way, 

 but well nigh impossible, if one is formed after the other. 



It is sufficient now to remark that the new phenomena 

 described above simulate in a rery striking way, what we 

 call gravitation and chemism. 



