Trans. N. Y. Ac. Set. 110 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 wns 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 beautiful plumb-like 

 crystals of pure sulphur. The temperature in all the openings in this 

 sulphur bed is high. At the surface of one ot 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 from a 

 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, from a 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 

 be of 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 Mariposa and 

 Prince Albert, 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 



