cS I eR ka 
Chemistry. 113 
2. Conductibility and specific heat of Thallium—Der 1a 
compared the conducting power of thallium with that of mercury by the 
method of Wheatstone. The density of the metal was found to be 
11,853 at 11° C., which agrees well with the determination of ion my, 
namely, 11,862 at 0° ; ; the density of the wire is 11,808. The conducting 
power of silver being taken as 100, that of mercury is 1°63, and that of 
thallium 8°64, a value which lies between those for lead and tin, and which 
is much lower than the corresponding values for the alkaline metals, 
The specific heat of thallium was found by Regnault to be 003355, as a 
mean of two experiments. The product of this number by the equiva- 
lent 204, gives 85°55, half of which is 42°77, so that thallium in its 
thermic relations is associated with the alkaline metals, and the formula 
of its protoxyd should be T,O if potash is written K,0,.— Comptes a hy 
ly, 887 and lvi, 588 
Ca a Ser: tr ere 
Bite were eee oe, PP ee 
er ere ee 
Pen a a Pere tee 
II. CHEMISTRY. 
O, 4 wo 3+ ag, and the acid in them is not precipitated by stronger 
acids. The ordinary tungstates contain the insoluble modification of 
formula 5RO, 1 2WO,. Lotz and Scheibler gave them the oat 
formula 3RO, 7 “WO, ‘but Marignac is disposed to return to the formula 
of Sea hy mecha ire ng the compounds, however, as double salts. The 
author did Javier in Mioiieg fluo-tungstates free from ips ee 
euseredie 4 id seat this respect with Berzelius, whose results 
expressed by the panel formula RO, WO,+RF, WFE,. Aecosdide 4 to 
Marignac, the same two salts combine i in other proportions also, but the 
most remarkable circumstance is the ps ie of cop 
CuO, WO,+CuF, WF,, with the fluo-silicate, fluo stannate and fluo- 
oe of ¢ copper, the last having the formula CUR, TiF,. This “nlp 
ism becomes intelligible when the formulas are written Cu,W,0?F,, 
and Cu,Ti,F,, so that it must be admitted that fluorine and oxygen may 
in certain cases replace each other atom for atom, though not equivalent 
for equivalent, and further that Berzelius’ mode of viewing the constitu- 
tion of the salt cannot be correct, since it furnishes no explanation of the 
oe The silico-tungstates form a new class of salts, and may 
ral be easily obtained by boiling a solution of an acid tungstate with 
c Inous silicic acid: they are easily soluble, and usually crystallize well. 
oe ye Bot.—Szcoxp Surtes, Vor. XXXVI, No. 106.—Juty, 1863. 
15 
