290 CHEMISTRY. 



wires of alloys with 25 i^er cent, of silver, platinum, and gold, elongated 

 11.7™°^, 6.14"^™, and 0.9°^'^ respectively. Witli six bichromate cells the 

 action was complete in an hour. After removing the battery the short- 

 ening took place in the same order, though less rapidly ; being for the 

 palladium wire only 2.6°^™ in 24 hours. The law of these variations was 

 automatically recorded. The coefficient of elasticity of x^alladium pure 

 fell from 15540 to 14000; and that of the silver alloy from 15240 to 

 12500.— (J. Phys., ix, 365, October, 1880.) 



Berthelot has quoted Pictet's exj)eriments on the liquefaction of oxy- 

 gen and hydrogen gases as illustrating his thermochemical views. The 

 oxygen was prepared by heating potassium chlorate. Now, the reac- 

 tion K CI 03 = K CI -f O3 according to Berthelot evolves 11 calories. 

 Hence, being exothermic and not limited by its inverse, it is not arrested 

 by a i)ressure of 320 atmospheres. The hydrogen was prepared hy the 

 action of potassium hydrate uiion the formate. Since K CHO2 -j- K O 

 H = K2 COa -f H2 evolves 18.4 calories, this action is also exothermic 

 and not limited by an inverse reaction. Hence, the gas should be evolved, 

 as Pictet found it to be, at over 600 atmospheres. Exothermic reactions 

 continue, then, whatever the pressure. — {Ann. Ghim. Phys., V, xv, 149, 

 October, 1878.) 



Thorpe has published the results of an extended research on the re- 

 lation between the molecular weights of substances and their specific 

 gravities when in a liquid state. He concludes : (1) that many isomeric 

 liquids, even of the sam^e chemical type, have not identical specific grav- 

 ities at their boiling points, and hence not identical specific volumes. 

 Since this occurs mainly in compounds of carbon and hydrogen, the in- 

 ference is that the specific volume of one or both of these bodies is not 

 absolutely invariable ; (2) that oxygen, sulphur, and nitrogen have also 

 variable specific volumes ; (3) that there is no evidence that the specific 

 volume of any other element is variable ; (4) that the number of these 

 latter atoms does not modify the volume, which is independent of the 

 molecular complexity -, (5) that the different members of a family of ele- 

 ments do not possess identical specific volumes, these volumes being 

 periodic functions of the atomic weights ; (6) that no evidence is aftbrde<l 

 that the specific volume is modified by any variation in the affinity value 

 of any element. — {Nature, xxii, 262, July, 1880.) 



Violle has determined the specific heat and melting point of ijalla- 

 dium, iridium, gold, and copper. For jialladium the specific heat was 

 found to be, at 0^, 0,0582 ; at 500°, 0.0682 ; at 1000°, 0.0782; at 1300°, 

 0.0842. For iridium, at Oo, 0.0317 ; at 500°, 0.0377 ; at 1000°, 0.0437, and 

 at 1400°, 0.0485. Gold has a specific heat at 0° of 0.0324 ; at 900°, 

 0.0345, and at 1020°, 0.0352. The fusing point of silver was found to 

 be 9540 C. referred to the air thermometer; of gold, 1035°; of copper, 

 10540 ; of palladium, 1500°; of platinum, 1775°, and of iridium, 1950°. 

 —{J. Phys., ix, 81, March, 1880.) 



Victor and Carl Meyer, in determining the vapor density of chlorine 



