CHP:MisTRy. 433 



Hydrates of gases. — Villard fiuds tliat wlien certain gases mixed with 

 aqueous vapor are condensed in Cailletet'a apparatus, crystalline hy- 

 drates are produced, which decompose spontaneously at the following 

 temperatures: Of CH4, at 2iP5; of CaH,-, at 120; of iJiUi at lS.o5; 

 of C2H2, at 14°; of 'NiO, at 12°. Nitrogen, hydrogen, carbonic oxide, 

 nitric oxide, cyanogen, ammonia, propylene, butylene, and all^ienegave 

 no crystals under similar conditions. (Oompt. lieud., cvi, 1002.) 



The formation of alloys. — The claim made by Spring that Wood's alloy 

 could be fornied from its component metals by means of pressure has 

 led Hallock to investigate the subject from another point of view. One 

 part cadmium, one part tin, two parts lead, and four parts bismuth, in 

 fine filings, were mixed in a glass tube of about five millimeters interior 

 diameter, closed at one end. The mixture was packed in the tube by. 

 gentle pressure with an iron wire, and the whole \Yas then suspended 

 in a water bath and exposed to a temperature of 98° to lOO^. Within 

 two days the entire mass was fluid, the alloy having formed at a tem- 

 perature 130^' below the melting point of its most fusible constituent. 

 The well-known alloy of sodium and potassium, which is liquid above 

 6° C, can be produced with great ease at ordinary' atmosjiheric tem- 

 peratures. When freshly cut surfaces of the two metals are gently pressed 

 together, liquefaction begins at the points of contact, almost instantly, 

 and spreads rapidly to completion. In short, it seems j)robable that all 

 alloys may be made from their components at temperatures little, if 

 any, in excess of their own melting noints. (Zeitschr. Physikal. Chem., 

 II, 379.) 



The same alloy of sodium and potassium has also been investigated 

 thermochemically by Joaunis, who prepared it by tlie usual method of 

 melting the two metals together under petroleum. The calorimetric 

 data given by the action of water upon this alloy, led Joaunis to con- 

 clude that the only true compound among the sodium-i)otassium alloys 

 is represented by the formula XaK^. ''Ann. de Chim. i'hys. (G), xii, 

 358.) 



The dehydration of metallic hydroxides by heat. — By experiments on 

 the temperature and rate of dehydration of hydrates corresponding to 

 sixteen metals, Carnelley and Walker conclude that Henry's views con- 

 cerning the polymerization of metallic oxides are mainly true. They 

 find that when a precipitated hydrate is heated, it gradually loses water 

 with the successive formation of a large number of definite hydrates, 

 each of which is further decomj)osed on a small rise in temperature, with 

 the formation of a compound containing a smaller j)roportion of water. 

 As the elimination of water i)roceeds, the residual molecule becomes 

 larger and more complex, until at last a highly complex molecule of 

 anhydrous oxide is left, of which the formula is some multiple of that 

 generally received. For the oxides of silicon, titanium, ;ind tin the coef- 

 ficient of polymerization must be at least ten, while oxide of zirconium 

 must be at least ZrajOjg, and antimonious oxide at least Sb3i,(>io. The 

 11. iAIis. M2 28 



