he Comstock vein, Nevada, were
exceptionally hot. At depths of from 1,500 to 2,000 feet, the thermometer
placed in a freshly drilled hole will show 130 degrees. Very large bodies
of water have run for years at 155 degrees, and smaller bodies at 170
degrees. The temperature of the air is kept down to 110 degrees by forcing
in fresh air cooled over ice.

Captain Wheeler, U.S. Engineers, estimated the heat extracted annually
from the Comstock by means of the water pumped out and cold air forced in,
as equal to that generated by the combustion of 55,560 tons of anthracite
coal or 97,700 cords of wood. Observations were then given upon
temperature at every 100 feet in the Forman shaft of the Overman mine,
running from 53 degrees at a depth of 100 feet to 121.2 degrees at a
depth of 2,300 feet. The temperature increased:

100 to 1,000 feet deep, increase 1 degree in 29 feet.
100 to 1,800 feet deep, increase 1 degree in 30.5 feet.
100 to 2,300 feet deep, increase 1 degree in 32.3 feet.

A table was presented giving the temperatures of a large number of deep
mines, tunnels, and artesian wells. The two coolest mines or tunnels are
in limestone, namely, Chanarcillo mines and Mont Cenis tunnel; and the two
hottest are in trachyte and the "coal measures," namely, the Comstock
mines in trachyte and the South Balgray in the "coal measures." Mr. Dorsey
considered that experience showed that limestone was the coolest
formation.

* * * * *

GALLISIN, AN UNFERMENTABLE SUBSTANCE IN STARCH SUGAR.

C. Schmitt and A. Coblenzl have made a careful investigation of the
unfermentable substances found in commercial starch sugars, and have
succeeded in isolating a definite compound, to which they give the name
gallisin. The method of separation and purification which they made use of
is as follows: 5 kilogrammes of commercial starch sugar were allowed to
ferment. At a temperature of 18-20 deg. C. and with a solution containing 20
per cent. the fermentation was complete in five to six days. It was
filtered; the perfectly clear, almost colorless, liquid evaporated as far
as possible on the water-bath, and the sirup while still warm brought into
a good-sized flask. The sirup was then well shaken with a large excess of
absolute alcohol, when it became viscous, but did not mix with the
alcohol. The latter was poured off, replaced by fresh alcohol, and again
shaken. When this shaking with alcohol