Earthy Matter spontaneously Comhustihle. 107 
passed through filtering paper, This was examined by re- 
agents. 
Sulphuric acid did not darken the solution^ consequently the 
absence of soluble vegetable matter was inferred. 
Alcoholic solution of iodine produced a muddy cinnamon 
colour, and a shining glassy film pervaded its surface. 
Muriate ammonia exhibited no traces of alumina. A slight 
effervescence was produced with water ^ as well as with diluted 
acids, probably attributable to the acid^cation qf the sulphur. 
Phosphate of soda, &c, gave, by a cloudy opacity, indications 
of magnesia. 
Oxalate of ammonia produced copious white cjouds, and in- 
dicated lime. 
Succinate of ammonia and tincture of galls, evinced the pre- 
sence of iron, which was more distinctly and less equivocally 
indicated by the prussiates ofpotassa and ammonia. 
Pure ammonia imparted a slight blue tinge, and a cylinder 
of polished iron, after some hours, exhibited a coppery film ; the 
presence copper was therefore presumed. 
Sulphur et of' ammonia changed the solution as blach as ink, 
Chromate of potassa produced a yellow precipitate, and hy-, 
droiodate of potassa yielded yellowlsEf^reen fiocculi, which sub- 
’ sequently settled into a lighter yellow colour ; lead, therefore, 
was clearly determined. 
As nitro-muriate of platimim indicated no change whatever, 
it was evident that potassa was absent. 
Solutions of silver evinced, by copious curdy precipitates, 
that muriates were present. 
Muriate wad nitrate oi baryta, in like manner, proved that 
sulphates abounded considerably. 
From these exhibitions, its probable constituents, on the effu- 
sion of water, are carbonaceous matter, muriate of soda and 
magnesia, and the sulphates of lime, lead, copper, and iron. 
Jts spontaneous ignition may be accounted for, by the united 
action of air and water on the sulphur, in contact with metal- 
line and carbonaceous matter, analogous to the phenomena some- 
times exhibited in the aluminous schistus at the Hurlet mine, 
near Paisley ; or, that of a paste of sulphur and iron-filings, 
when moistened. 
