416 Sir W. Congreve oh [JuKE, 



tore, to be left for some time on the premises, so as to become 

 more or less nuisances to the public. 



At present the system is far from perfect in any respect. It 

 is hoped, therefore, that every possible encouragement v. ill be 

 given by the different companies to that description of investi- 

 gation and experiment calculated to promote improvement, 

 although no immediate profit may result to the companies. 



It is also very desirable, that when any improvement is rea- 

 lized by any particular company, that it should be generally 

 adopted by the rest ; and by the due exertion of this spirit, I 

 have but little doubt that a great degree of perfection, both as 

 to convenience and security, may be looked for at no distant 

 period. 



Great care, however, is unquestionably requisite, and there 

 are certain points, the observance of which by the different 

 companies is so essential, that any indifference or neglect as to 

 them must be vigilantly prevented ; for it must be obvious that 

 the vast accumulation of inflammable gas necessary to carry on 

 this mode of illumination, in its present extended state, must be 

 attended with more or less risk, according to the conduct of 

 those employed. To explain, therefore, somewhat more defi- 

 nitely than has hitherto been done, the nature and extent of this 

 risk, I have caused the following experiments to be tried at 

 Woolwich since my last Report, with a view to bring the explo- 

 forces of different mixtures of carburetted hydrogen and 



sive 



atmospheric air into a comparison with gunpowder. 



The results are as follow : — The following mixture was fired 

 from a cylinder constructed for this purpose, to project a ball 

 weighing 7 lbs. 2 oz. ; the cylinder being suspended by a pen- 

 dulum, to measure the degrees of recoil. 



First experiment. 



Ranged the ball, "| 

 on an average > 

 of three rounds. J 



94 



64 c 



Carburetted hydrogen, 288" 

 cubic inches, and 1,440 

 cubic inches of common 

 air, being in the propor- 

 tion of one-sixth of hy- 

 drogen to five-sixths of 

 atmospheric air, were 

 fired. 



Gunpowder (8 drachms)^ Average 

 was found to produce > of the 

 nearly the same effect. J ball. 



It appears, therefore, that mixed in this proportion, viz. one- 

 sixth of carburetted hydrogen to five-sixths of common air, one 

 cubic foot of this gas would be equal to three ounces of gunpow- 

 der ; that 480 cubic feet are, therefore, equal to one barrel ; and 

 that the contents of one gasometer of 15,000 cubic feet are 



range 

 same 



1 

 J 



Feet. 



Average recoil 

 of cylinder. 



64 





