102 Experiments on Anthracite, Plumbago, &c. 
Arr. XIIf.— Experiments on Anthracite, Plumbago, §c. By 
Larpner Vanuxem. Read March 15, 1825.* 
Tuese experiments were undertaken with a view to 
determine whether the globules obtained by Professor 
Silliman, from the above substances, were owing to a fusion 
of their carbon, or merely to the impurities or foreign matter 
contained within them. ‘They were long delayed by my 
waiting for some sheet zinc necessary to repair a Deflagrator 
intended to be used for the purpose of obtaining the globules ; 
but this not arriving, | resolved to avail myself of the sugges- 
tion of Professor Silliman, namely, that of using the com- 
pound blowpipe which answered perfectly well. In the ex- 
periments with the blowpipe, the substances were placed 
upon platina foil, spread upon a lump of magnesia ; the size 
of the pieces subjected to its action, was about } an inch in 
diameter, and ! of an inch in thickness. The light in the 
greater number of instances, was so intense, that | found it 
necessary to use double green glasses. 
The mode pursued in the analysis of Anthracite and Plum- 
bago was as follows. ‘The presence of water was ascertained 
by heating a few small pieces of the substance in a glass 
tube, closed at one end; andthe quantity of water by heating 
a given portion in a covered platina crucible. Another por- 
tion was pulverized in an agate mortar; then a given weight 
of it was put into a platina crucible, and kept without its 
cover at a red heat in a small French furnace, until the whole 
of the carbon was consumed; the residue was then boiled in 
water for an alkali; after this operation it was heated with 
caustic potash ina silver crucible: when the fusion of the 
mass was completed, water was added, and the whole then 
dissolved with nitro-muriatic acid. By evaporating the li- 
quor to dryness, and adding acidulated water and filtering, 
the silex was obtained. To the liquor from this operation, 
ammonia in excess was added, and by this agent, the iron, 
manganese, and alumine contained in the liquor, were precip- 
*From the Journal of the Academy of Natural Sciences of Phil- 
adelphia. 
