78 Chronicles of Science. [Jan., 
has noticed the formation of what he believes to be a Hydrate of 
Sulphide of Carbon. If a little water is placed on a glass plate, 
and a watch-glass full of the bisulphide is set in the midst and 
then blown upon, the water soon congeals, and the watch-glass is 
filled with snow-white flakes of the supposed hydrate. A lighted 
coal brought to the snowy mass sets fire to the bisulphide, which 
burns away, leaving the water with which it had united. The 
author has several times determined the amount of the water, and 
finds it to be constant, and just the quantity required by the 
formula 2 C §,, H, O. 
The formation of this substance, we may add, is easily shown in 
another way. Ifa stream of the bisulphide is made to trickle down 
a piece of loose twine, the twine quickly becomes covered with a 
thick crust resembling hoar-frost. ‘The substance, whatever it may 
be, rapidly evaporates, leaving the twine perfectly dry. 
A new process for the production of sulphuric acid has been 
patented in France, and probably in England, by MM. Tardani and 
De Susini. Its great recommendation is that it dispenses with the 
large leaden chambers necessary to the English process. We must 
refer our readers to the source indicated below* for full particulars, 
and need only say that the Sulphur or Pyrites is burned in com- 
pressed air, and the sulphurous acid is first washed to free it from 
arsenic and other contaminations, and is then brought in contact 
with the nitric vapours in a small leaden chamber of peculiar 
construction. ‘The reactions are precisely the same as in the old 
mode: the apparatus, however, it is said, occupies forty times less 
space, and an acid is obtained free from the ordinary impurities. 
A new process for the manufacture of Soda has also been 
patented in France by M. Kessler. As in Leblanc’s process, the 
imventor starts with common salt. This is intimately mixed with 
sesquioxide of chromium, either alone or with peroxide of man- 
ganese, and then roasted in a current of steam. The result is the 
evolution of hydrochloric acid, and the formation of chromate of 
soda. When the evolution of hydrochloric acid has ceased, the 
charge is drawn from the furnace, mixed with a proportion of 
charcoal or coal, and then reburnt. In this way the chromate of 
soda is converted into carbonate with the reproduction of sesquioxide 
of chromium. The soda is separated by lixiviation, and the sesqui- 
oxide is reserved for a future operation. 
Two other technical processes deserve a short notice. One is 
for the extraction of indigo from rags dyed with that substance. 
The rags are first saturated with a weak solution of caustic soda, 
then placed in a boiler with a double bottom, and exposed for some 
hours to steam at 45lbs. pressure. The indigo in the rags is 
* «Bulletin de la Société Chimique de Paris,’ Oct., 1867, p. 295. 
