Trans. N. Y. Ac. Scé. 170 May 22, 
surface of the strange little desert the sulphur outcrops in many places, 
forming ledges of sulphur; and a number of prospects show an abund- 
ance of quite pure material. A shaft was sunk in the centre of this 
deposit, to the depth of twenty-five feet, all in pure sulphur, as I was in- 
formed by Mr. Semler. The material taken from this shaft has been 
returned to it, in order to guard against the burning of the mine, and 
the broken fragments are now cemented into a solid mass by the sul- 
phur that has been deposited in the interstices between the broken 
masses. The deposition of sulphur is still in progress, the prospecting 
holes becoming lined in a few days with most beautifui plumb-like 
crystals of pure sulphur. The temperature in all the openings in this 
sulphur bed is high. At the surface of one of the prospecting holes 
which had been refilled with broken fragments, the thermometer read 
104° F,; and through all the openings vapor and heated gases are con- 
stantly escaping. In cold weather the clouds of vapor forming above 
this mine may be observed from a distance of a mile or two. The 
drops of moisture that condense on any cold object held for a moment 
in the excavations, are intensely acid, and from their taste seem to a 
contain a large proportion of sulphuric acid. No chemical examinations 
of these acid drops or of the gases that are constantly escaping from 
the openings could be made. It is noticeable, however, that no odor of 
sulphuretted hydrogen can be detected about the mines; but froma 
few simple tests, and from the presence of dead animals in a large 
number of the openings, it seems evident that carbonic acid is exhaled 
in large quantities. The sulphur at this locality covers a circular area 
of about 1000 feet in diameter, and, from the prospects that have been re- 
ported, cannot be less than twenty-five feet thick. This is not pure sul- 
phur, however, but certainly carries a large percentage of earthy mat- 
ter. 
The conclusion arrived at, froma hurried inspection of this interesting 
locality, is that the sulphur fills a nearly extinct solfatara, into which it 
has been conducted from below, seemingly by direct sublimation, or, 
what is perhaps more probable, by the decomposition of sulphurous 
gases, and the deposition of the liberated sulphur. A careful examin- 
ation of the fumes that are exhaled from these openings would certainly 
beof much value in determining the chemical history of sulphur de- 
posits. 
Of the second class of mines—those in which the sulphur impreg- 
nates beds of volcanic tuff—we have examples in the JZ/arzfosa and 
Prince Alvert, situated at the base of the mountains, two miles east of 
the fort at Cove Creek. At these localities the tuff is stratified, and 
contains scattered pebbles of quartzite and limestone, and is impreg- 
nated over a large area with sulphur, which fills all the interstices of 
