THE ALKALINE AND BOR A Cl C LARES OF CALIFORNIA. 159 
of the lake, and extend over an area equivalent to one-third of 
its surface ; they are, however, also met with in smaller quanti- 
ties in the muddy deposit of other portions of the basin. The 
largest crystals, some of which are considerably above a pound 
in weight, are generally enclosed in a stiff blue clay, at a depth 
of between three and four feet ; and a short distance above them 
is a nearly pure stratum, from two to three inches in thickness, 
of smaller ones ; in addition to which crystals of various sizes are 
disseminated through the blue clayey deposit of which the 
bottom consists. 
Besides the borax thus existing in a crystallized form, the 
mud itself is highly charged with that salt, and, according to an 
analysis by Dr. Oxland, affords, when dried, in those portions of 
the lake which have been worked (including the enclosed crys- 
tals), 17*73 per cent. Another analysis of an average sample, 
by Mr. Gr. E. Moore, of San Francisco, yielded 18*86 per cent, 
of crystallized borax. In addition to this the deposit at the 
bottom of the other portions of the basin, although less produc- 
tive, still contains a large amount of borax. 
Water collected from Borax Lake, in September, 1863, was 
found by Mr. Moore to contain 2401*56 grains of solid matter 
to the gallon, of which about one-half was common salt, one 
quarter carbonate of sodium, and the remainder chiefly anhyd- 
rous borax, equal to 535*08 grains of crystallized salt to the 
gallon. Traces of iodine and bromine were also detected. A 
sample of water taken from the interior of a coffer-dam sunk in 
the middle of the lake, and which had been allowed to fill by 
percolation from the bottom upwards, was found to be more 
concentrated, yielding 3573*46 grains of solid matter to the 
gallon, but it contained the same iDgredients, and in nearly the 
same proportions, as the water from the lake itself. When 
evaporated to dryness, this water yields a considerable quantity 
of finely divided carbon, resulting from the various organic 
bodies which have been dissolved in it. 
Mud from the bottom of Borax Lake is in high repute among 
the local Indians as an insecticide , and is used in the following 
way. The head of the patient is thickly plastered with mud, 
which is well rubbed in, and then allowed to become perfectly 
dry ; when dry, it is removed by rubbing between the hands, 
and with it disappears the colony of parasites. Ordinary clay 
is, under pressure of circumstances, sometimes employed for 
this process of shampooing, but when alkaline or boracic mud 
is available, it is considered more efficacious. 
When this locality was visited by me in 1866, borax was manu- 
factured exclusively from the native crystals of crude salt, while 
the mud in which they were found was returned to the lake after 
a mechanical separation of the crystals by washing. The extrac- 
