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.

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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 has been repeated several times, the sirup is finally changed to a yellowish-gray mass.  This is now brought into a large mortar, and rubbed up under a mixture of alcohol and ether.  After some time the whole mass is transformed into a gray powder.  It is quickly filtered off with the aid of an aspirator, washed with alcohol and then with ether, and brought under a desiccator with concentrated sulphuric acid.  In order to purify the substance, it is dissolved in water and treated with bone-black.  The solution is then evaporated to a sirup, and this poured into a mixture of equal parts of anhydrous alcohol and ether.  In this way the new compound is obtained as a very fine, pure white powder which rapidly settles.  It has much the appearance of starch.  Under the microscope it is perfectly amorphous.  In the air it deliquesces much more rapidly than ignited calcium chloride.

Treated with dilute mineral acids or oxalic acid on the water-bath gallisin is transformed into dextrose.  It does not ferment when treated in water solution with fresh yeast.  The analyses led to the formula C_{12}H_{24}O_{10}.  When treated under pressure with three times its weight of acetic anhydride at 130-140 deg. it dissolves perfectly.  From the solution a product was separated which on analysis gave results agreeing with the formula C_{12}H_{18}O_{10}(C_{2}H_{3}O)_{6}.  The substance appears therefore to be hexacetylgallisin.