482 RECORD OF SCIENCE FOR 1887 AND 1888. 



not exist iu the gaseous state. For chrouious chloride the data give a 

 deusitj considerably too high for CrClg; but the compound vaporizes 

 with difficulty, and the density diminishes with rise of temperature. 

 CrOi is probably the true formula. (Journ. Chem. Soc, liii, 828.) 



Gallium. — According to Nilson and Petterson the trichloride of this 

 metal has a vapor density which at 350° is 8.846, at 606o is 6.144, and 

 at 1,000-1,100° is 5.185. GagCle requires 12.16. GaCl3 requires 6.08. 

 The latter value is probably correct. They also describe a dichloride 

 whose vapor density agrees with the symbol GaCl^. (Journ. Chem. 

 Soc, LIII, 822.) 



In this case also Nilson and Petterson are partly controverted by 

 Friedei and Crafts, who find the trichloride of gallium, as measured at 

 273°, to be GajClg. Above this temperature it begins to dissociate, per- 

 haps into 2 GaCl;,. (Compt. Eend., cvii, 306.) 



For indium, Nilson and Petterson re-examined the trichloride, and 

 also describe two new compounds, a mono- and dichloride, respectively. 

 The vapor densities of the three compounds indicate molecules of InCls, 

 InCU, and InCl. (Journ. Chem. Soc, Liii, 816.) The density of the 

 trichloride is also given by Biltz, who liuds it concordant with InCls. 

 (Berichte, XXI, 2766.) All of the foregoing data relative to the iron- 

 aluminum group are well summarized by Sydney Young, who gives 

 them ill tabular form in Nature for December 27, 1888. His note is 

 discussed by Brauner in the same journal for January 31,1889. 



The vapor density of tellurium tetrachloride has been studied by 

 Michaelis. It boils at 380°, and up to 448° it distills undecomposed. 

 Even at 530 it is scarcely dissociated at all, and its density indicates a 

 molecule of TeCl4. Hence tellurium is at least quadrivalent. (Berichte, 

 XX, 1780.) 



Refrifjeraiing mixtures. — The freezing mixtures containing soliditied 

 carbon dioxide have been carefully studied by Cailletet and Colardeau, 

 who give the following determinations of temperature : 



° c. 



Solid carbon dioxide — 60 



Solid carbon dioxide iu vacuo — 76 



Solid carbou dioxide iu ether — 77 



Same mixture iu vacuo - 103 



The following all represent ordinary pressures : 



o 



Solid carbou dioxide iu methyl chloride . —82 



Solid carbou dioxide iu sulphur dioxide —82 



S(did carbou dioxide in amyl acetate —78 



Solid carbou dioxide in phosphorus trichloride —76 



Solid carbon dioxide in absolute alcohol —72 



Solid carbou dioxide in ethylene chloride — 60 



In the three comi)ounds last named the carbon dioxide was manifestly 

 less soluble than in the others. Hence a smaller reduction of tempera- 

 ture as compared with that ot the original solid. (Compt. liend., cviii, 

 1631.) 



