e 
y 
THE GEYSERS OF CALIFORNIA. 341 
This leads next to the subject of incrustations, which 
for our purpose we may divide into three groups, namely : 
silicic acid, sulphates, and sulphur. The first comprises 
the crystals of quartz, which are found upon slates embed- 
ded in the soil. They are minute, but very perfect. 
The sulphates, such as crystals of ferric and magnesic 
sulphate, and the alums were not seen in their best es- 
tate. The rain of May 28th had dissolved the largest 
ones, and while we regretted this loss, we consoled our- 
selves with the thought that the rain, which had robbed 
us of our jewels, had added intensity to the chemical ac- 
tion going on around and below. It is stated upon good 
authority that the action is more intense during, or at 
the close of the rainy season, which is the winter of Cali- 
ornia. 
The sublimed sulphur presents the two prevailing 
forms; namely, that which has crystallized with free 
access of air, and resembles the obtuse oblique rhombic 
prisms of sulphur familiar to chemists; and that which is 
produced under pressure, and has a slight inclination of 
the vertical axis. 
In some limited localities there are effloresced salts, 
and pale, faded carbonates. At one spot, a light green 
cupric carbonate was partially covered with a darker 
green confervoid growth, and each shaded into the other 
like colors on a palette. 
But the salts just referred to are those which have been 
left by the heavily charged water. Imagine, therefore, the 
Variety of dissolved salts which must have been formed, 
by the over-heated steam and sulphur acids, from. the 
rocks which are being so rapidly leached under pressure. 
The solutions are, almost in every case, acidulated by a 
high sulphur acid; free sulphur floats in the water, and 
