158 W. E. Woodbridge on the Pressure of Fired Gunpowder. 



the instrument was made at the temperature at which the gun 

 was fired. In the brass gun several holes were made for receiv- 

 ing the instrument at different distances (specified in the table) 

 from the bottom of the bore. When not in use, these holes 

 were closed by plugs fitted to each. 



In the experiment with the musket barrel, a part of the 

 breech-end, in the rear of the charge, was made to serve as a 

 substitute for the cavity of the screw plug, in receiving the pie- 

 zometer. 



The experiments are to be regarded altogether as preliminary 

 trials, but they are not, I hope, without interest and value. The 

 following table presents the most interesting of the results. 



Experiments on the pressure of fired Gunpowder. 





Powder. 



Shot. 



Dist'nce of 



o ° 



£ 1 

















piezomet'r 





3 3 





Remarks. 



GUN 



Weig't. 



Height. 



Weight, 

 (strap'd ) 



Diam. 



fr id bott'm 

 of bore. 



C 3 3 



e*> til 



3* CU.3 







lbs. 



in. 



lbs. 



in. 





Fahr. 



~ lbs. 







r 



125 



3-5 



640 



3 58 



(8*26) 



56°5 



9640 



1 ) Piezomet'r attach'dto 







632 





04 



10140 





S the bottom of the bore 



1 



Iron J 

 6 pdr. 



■ 



3'42 

 3 35 



633 

 633 



" 



15 



55° 5 

 50° 



14260 

 16070 





Powder without cart- 

 ► ridge bags. 





3-42 



639 







04 



1 4Q i 0 



It* 





1*5 



4-0 



6 32 

 633 





u 



53° 

 50° 



I to iv 



18630 













629 



u 





47° 









r 





4 00 



fi mi 



O O 1 



tt 



l 



0» 



208 1 0 



In this and subsequent fir- 







6 37 







58° 



20630 





ings, powder in cartr'ge 







435 



635 





a 



58° 



19810 





bags. 







455 



636 



3 575 



4 



53° 



16510 



Mean of 3 rounds. 









6 34 





7-8 



50° 



9575 



Mean of 2 rounds. 





« 



ft 



6-39 





11-8 



44° 



7740 



Mean of 3 rounds. 









6-38 





15 8 



52° 



9570 







Brass 





a 



6 29 





23-8 



50° 



8760 









tt 



633 





31 8 



6930 





u u tt 



6 pdr/ 



it 



a 



636 

 634 





398 

 47-8 





5380 

 5910 





it tt tt 

 tt tt tt 







4-48 



6 11 



a 



1 





16260 



Mean of 2 rounds. Naked 





a 



4-65 



0 





« 





5480 





balls. 





2-0 



6 05 



0 









9780 









3-0 



8-8 



0 







«< 



14820 









2-0 



565 



6-36 



3-575 







20640 



Mean of 2 rounds. 





30 



885 



6-43 









22220 







Iron J 



1-5 



4-38 



12-16 

 12-14 



3-66 



1-5 



« 



20480 

 20780 



Cylinders equal to 2 balls. 



« it it 



B pdr. 1 







1215 



a 



a 



60° 



20970 





u tt a 





grains. 



in. 



grs. 









lbs. 









70 



0-7 



666 



0-675 



0 



60° 



2730 



Expanding ball. 

 * Round ball and paper as 

 for cartridge. 



M j 



GO A 



110 



ris 



420* 



•65 



0 





3820 



P 



3 



310 



3-55 



464* 



•675 



0 





15170 



2d proof charge. 



389 



4-2 







0 





18500,1st proof charge. 



In the first two experiments recorded in the preceding table 

 the orifice of the piezometer was inches from the bottom of 



