ee 
154 WL. We vbr idge on the Pressure of Fired Gunpowder. a 
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_sive rupture to time are but imperfectly known. ’ 
The following experiment seems to show that the extreme — 
force of gunpowder fired in small quantities does not exceed ~ 
6200 atmospheres. I enclosed in a hollow cylinder of cast-steel — 
14 inch in exterior diameter and 4 inch in diameter interiorly, — 
20 grains of Hazzard’s Kentucky rifle powder, which filled, — 
loosely, the cavity. This was fired by a flash of powder péne- — 
trating through the aperture of a valve (of steel) opening inward, ~ 
but designed to prevent the escape of gas outward. ‘The cylin- ~ 
der was not ruptured, and being put under water, no gas wai 
found to escape. (The weight of the instrument was too 
to test the loss of gas by my scales.) On pressing in the valve 
by means of a screw, an abundance of gas escaped, carryin 
with it the odor of sulphuretted hydrogen. The seat of the valve 
was found to remain eat a fact which when compared wi 
calculated strength of the cylinder would be equal to an inte 
ressure of about 93000 lbs. per square inch, or 6200 atm 
