The material result of this experiment was as follows:--With 261 days' work and 139-1/2 lbs. of powder, 202 buckets of stone were removed; while in the preceding week, using common powder (schaghticoke) with 251-3/4 days' labor and 236 lbs. of powder, 168 buckets of stone were taken out. The cost of the experimental powder is about twice as expensive as the common powder, and its superior strength is apparent from the above result. EXPERIMENTS WITH NITRO-GLYCERINE. During the summer, some experiments have been made with this explosive agent. A quantity, costing $934.29, was brought to the works by Colonel Schaffner, who exhibited the action of the material in various ways, with a view of testing its power, and the comparative safety of introducing it instead of powder. After repeated trials outside of the works, during which about three-fifths of the material was consumed, it was introduced into the tunnel at the West Shaft with the following result: It was used for three days at the East heading of the West Shaft; the advance made in the heading was for the time, 14-1/2 feet;--being an advance of 4.82 feet per day, and at the rate of 125.33 feet per month. In these three days there were taken out of the enlargement 151.76 yards of stone. To remove this quantity with powder would cost, on an average, per yard, $9 84 Actual cost with glycerine, 6 20 ----- Difference, $3 64 Multiplied by 151.76, gives. $552 40 In the same time there was removed of heading 60.15 yards. To remove an equal amount by powder costs, per yard, $16 25 Actual cost with glycerine, per yard, 6 05 ------ Difference, $10 20 $10.20 multiplied by 60.15, gives 613 53 -------- $1,165 93 Cost of the glycerine used during the three days, being 2/5 of $934.29, 350 36 -------- Saved, by using glycerine, in three days, $815 57 Which is a saving by the use of glycerine, per day, of $276 85.4 and allowing three hundred successful working days in the year, an annual saving of $81,557 40