Chemistry and Physics. ae 
the ethylide of wees described by Buckton. Its formation may be 
represented by the equation 
Ha(C2Els)I-4-22n (Calls) =H OcHls)2-4 Zn(OsHs)-4Znl. 
This result exhibits a mobility in the uae groups of these compounds 
which could scarcely have been expec 
the action of zine-methyl nee the chlorid of mercur-ethyl and 
subsequent distillation, the author obtained only a mixture of ethylide of 
mercury, Hg(CsHs)2, and methylide of mercury, Hg(C2H3)2, but con- 
siders it probable that in the above reaction an ethylomethylide of mer- 
Pie is actually formed, but that this is subsequently decomposed by dis- 
tillation. 
In a previous memoir, the author showed that the vapor density of 
zinc-ethyl requires the formula Zn2 i Calis} nevertheless it was not found 
CaHs 
—— to pind the intermediate sicieniesite Zn? io CoHs 
in ether is treated with zinc in the co digester, zinc-methyl is formed 
in large quantity, but - distillation a body 3 is obtained which has the 
formula 2Zn2 rant mc ib Cy aa O2, and which therefore anyon to be a 
methy] vapor and ether vapor in the above proportions would 
density 3°0413, without however definitely adopting either view. has: 
er Chemie und Pharmacie, exi, 44. 
4, On the isomorphism of stannic, silicic, and zirconic acids.—The ob- 
servation of Marrenac that the fluostannates and fluosilicates are isomor- 
phous, renders it necessary to assume that silicic acid, like stannic acid, 
- contains two equivalents of oxygen . Rose di rects attention to ‘the 
fact that zircon has the same crystalline form as yee and with 
this also in the cleavages. The isomorphism o este with one of the 
orms of titanic acid is still more close, although peter pr not like ru- 
tile and tinstone been found in twin crystals. The author remarks that 
zircon must be regarded as an isomorphous sesame of one atom of 
zirconic and one atom of silicic acids. It appears however that there are 
some varieties of zircon in which the two acids are onite in ratios. 
Hermann has examined a it pe sect Fo two atoms of zirconic and 
three of silicic acids, and has ed the mineral rie iadchie® it has 
the same crystalline form as salaaiy a zircon.— Ann, der Physik und 
hemie, evii, 602. 
6. On the equivalent of manganese.— —The equivalent of manganese 
was determined by Berzsxtvs as 27°56, from two analyses of the chlorid. 
Von Hauer has recently found for this equivalent the number 27°5 by 
Fee 2 anhydrous a of manganese by sulphuretted hydrogen to 
Iphid of manganese. His result, 27°5, was the mean of nine experi- 
