Chemistry and Physios. 227 



of ammonia, but strongly attacking the mucous surfaces when 

 breathed. The gas is very readily soluble in water, blues red- 

 dened litmus paper strongly, and when not too dilute produces 

 white fumes with hydrogen chloride. It is exceedingly per- 

 manent on heatings but has a powerful reducing action. Feh- 

 ling's solution and ammoniacal solution of silver are at once 

 reduced, and neutral copper sulphate yields a dense red precipi- 

 tate with it. Mercuric chloride is reduced by it to mercurous 

 chloride. Its salts evolve gas actively when mixed with nitrites. 

 — Ber. Berl. Chem. Ges., xx, 1634, June, 1887. g. f. b. 



7. Method of observing the action of Magnets on Liquids • 

 by S. T. Morehbad. — Some weeks ago one of my students, Mr. 

 J. C. Child, and myself were working with a diamagnetic instru- 

 ment, simply repeating well known experiments. Pliicker's 

 method of observing the diamagnetism of liquids having failed 

 in our hands to give satisfactory results, we hit upon a method 

 which was new to us and which was very satisfactory. Into a 

 glass tube of about four or five millimeters internal diameter a 

 small quantity of liquid was introduced forming a short cylinder. 

 This tube was placed, horizontally at right angles to the line join- 

 ing the poles of the magnet with the liquid nearly between the 

 poles. When the current was turned on, the liquid was very evi- 

 dently repelled. Water was repelled through a distance of about 

 half a centimeter ; wood spirit through a greater distance. By 

 moving the tube in the direction of its length the wood spirit 

 could be pushed any distance through the tube. The amount of 

 motion is of course a function of the resistances due to adhesion 

 and friction as well as of the repulsive force. The attraction of 

 liquids is easily shown by the same method. 



A single modification of the above plan of proceeding is to in- 

 cline the tube slightly so as to make the liquid flow toward the 

 poles. If the required velocity be not too great the magnet acts 

 as a break to stop the motion. It is well to bend the tube up a 

 little at each end to prevent the liquids from flowing out. This 

 method is well adapted for projection so as to be seen by large 

 audiences. 



"Washington and Lee University, Lexington, Va., May 9, 1887. 



8. Comparison of the radiations from melting platinum and 

 silver. — M. J. Viollb has studied these radiations by means of a 

 thermopile, one surface of which received the radiations and the 

 other was exposed to a known source of heat in such a manner as 

 to bring the needle of the galvanometer to zero. It was found 

 that the total radiation of melting platinum is fifty-four times that 

 of melting silver. — Comptes Bendus, July 18, 1887, p. 163. j. t. 



9. Solidification of liquids by pressure ; M. E. H. Amagat has 

 succeeded in solidifying bichloride of carbon (C 2 C1 4 ) by pressure. 

 The disposition of his apparatus enabled him to photograph the 

 resulting crystalline body. C a C 4 solidifies under the following 

 conditions. 



