316 Scientific Intelligence. 
= examined to see if they melt. Various devices are employed 
applying the method, which are described in the paper. In 
the case of ae for example, NaClO, melts in its vapor while 
NaN 
s between 339° and 359°. Thallous iodide TH, Pepdint melts 
NaCl and Pb(PO,), but not PbP,O, or Na,CO,; boiling point 
d 
° 
is therefore ee 800° and 806°. The Pabare habe shortly to 
i 
. S.. Gk 
On the Va apor Density of Thallous chloride and Lead 
chloride.—Roscox has simplified Deville and Troost’s method of 
vapor density, ok only to give it sufficient accuracy to fix 
molecular aie oy A hn 5 a aaa globe, of about 
300 c.c. capacity, ponte ining from 3 to 9 grams of the substance 
to bee magneto is lo ec closed ith a stopper of burned clay an 
amount of substance it contains is determined by analysis e 
temperature of the muffle is fixed calorimetrically it pri in 
it at the same time a weight of platinum of known val 
den sity 0 ar mercury vapor was found to be 6° 92, 6° 15, 6°91, 5°77, 
and 668 as a mean. In the case of thallous chloride 
seven expe eriments, at eae eae of 859°, 828°, 1015°, 849°, 
1026°, 852° and 837°, gave 815, 8°28, 8°06, 7-43, 8°75, 8°60 and 
7°84 as the density of its vapor. The calculated value, eee 
the molecular weight to be 238°07 and the formula TICL, is 8 
e vapor density of lead chloride determined in this way, ae 
however a higher temperature, was 9°12, 9°72, 9°51 and 9°64, 
1046°, 1089°, 1077° and 1070° respectively, the theoretical value 
for PbCl, with a molecular weight of 277:14, being 9 
Berl. Chem. Ges., xi, 1196, June, 1878. 
heated to redness and steam driven through it, the gas evolved 
being collected over water, and analyzed by Bunsen’s method. 
In the first series of experiments, the results were not uniform for 
sites portions of gas, the CO, increasing and the CO dimin- 
ing. Moreover, two volumes of hydrogen should appear for 
ne volume of CO, and one for each volume of CO; but this 
was not the case, the hydrogen being always too low. These 
