334 Dr A. Voelcker on the 
greater is the deviation from the composition of common 
coal. On the other hand, the more an anthracite resembles 
common coal in its physical character, the closer is the ap- 
proximation to the latter in chemical composition. The sul- 
phur which has been found in every specimen of anthracite 
in which it has been sought for, is generally considered as ex- 
isting in it as well as in coal, in combination with iron, as 
iron pyrites, but the subjoined results shew that the sulphur 
found in anthracite does not always occur in the form of 
iron pyrites, but is, in part at least, in combination with 
the organic elements of the mineral. In the following ana- 
lyses the greatest care was taken to deprive the anthracite 
of any hygroscopic water, by keeping it finely powdered in a 
glass tube, at a temperature of about 230° F., and passing 
over it a current of dry air for several hours. 
The per-centage of carbon was ascertained by burning from 
three to four grains with a mixture of oxide of copper and 
oxide of lead, and the simultaneous application of oxygen gas, 
in order to secure complete combustion of the carbon. The 
oxygen, for that purpose, was disengaged from chlorate of 
potash, mixed with pure oxide of copper, and placed at the 
closed end of the combustion-tube. A mixture of the oxides of 
copper and lead possesses the advantage over pure oxide of 
copper, of being much less hygroscopic ; for that reason it is 
peculiarly adapted for combustions in which the exact amount 
of hydrogen is to be ascertained. The nitrogen was deter- 
mined according to Will and Varrentrapp’s method, by heat- 
ing the finely-powdered anthracite with soda-lime in the 
usual way. 
For the determination of ash about 10 grains were burned 
in a platina capsule. The ash was coloured red by oxide of 
iron. 
The proportion of sulphur was ascertained by introducing, 
into a red-hot crucible, a mixture of anthracite with carbonate 
of soda and nitre, in small quantities at a time, and heating 
the whole afterwards a little more strongly. The resulting 
fused and perfectly white mass was dissolved in water, super- 
saturated with hydrochloric acid, and the sulphuric acid then 
precipitated with chloride of barium. 
So ee ny olin ee ee ee ee ee 
