2 Experiments iipou Gunpowder. 



moderately warm for the season. In order that each 

 experiment might, as nearly as possible, be made under 

 similar circumstances, they were all made between the 

 hours of ten in the morning and five in the afternoon ; 

 and after each experiment the piece was wiped out with 

 tow till the inside of its bore was perfectly clean, and as 

 bright as if it had just come out of the hands of the 

 maker ; and great care was taken to allow as much 

 time to elapse between the firings as was necessary to 

 render the heat of the barrel nearly the same in every 

 experiment. 



A Description of the Apparatus. 



The barrel principally used in these experiments 

 was made by Wogdon, one of the most famous gun- 

 smiths in London ; and nothing can exceed the accu- 

 racy with which it is bored, or the fineness of the 

 polish on the inside. It is made of the very best iron, 

 and, agreeably to Mr. Robins's advice, .1 took care to 

 have it well fortified in every part, that there might be 

 no danger of its bursting. Its weight and dimensions 

 may be seen in the table of the weight and dimensions 

 of the apparatus, p. 14. 



Fig. i represents a longitudinal section of a part 

 of the barrel, with the apparatus first made use of for 

 shifting the vent from one part of the chamber to 

 another, or rather for moving the bottom of the cham- 

 ber further from, or bringing it nearer to, the vent, 

 in order that the fire might be communicated to the 

 powder in different parts of the charge. 



a y by represent the lower part of the barrel, c is the 

 breech-pin, which is perforated with a hole four tenths 



