418 Sir W. Congreve on [June, 



house ; by the oversetting of a gasometer, from the breaking of 

 its chain of suspension, an accident which lately happened at 

 Brighton, and which has happened also by the bursting of the 

 tank in which the gasometer floats. The constant leakage of 

 an old gasometer is also a probable cause of explosive mixture. 

 At all events, these are evidently probabilities of accident quite 

 sufficient to show the absolute necessity of the utmost vigilance 

 and precaution. 



But even supposing this mixture not to take place, I appre- 

 hend that serious consequences might attach to the mere inflam- 

 mation and combustion of a large deposit of inflammable air, 

 even in an unexplosive state. 



It appears to me, that such a combustion, by lightning or 

 otherwise, would produce very destructive effects to the neigh- 

 bouring buildings, and gasometers, merely by the sudden ratifi- 

 cation and expansion of the air caused by it, and would, in fact, 

 produce a violent detonation and concussion, without supposing 

 any combination of oxygen and hydrogen, but merely by the 

 simple conflagration of the hydrogen ; under these circum- 

 stances, and especially with reference to the experiments made 

 at Woolwich, by which it appears, that the explosive force is 

 greater than has usually been assigned,* I shall feel it right in 

 concluding this Report, distinctly to point out such precautions, 

 in this and in other respects, as 1 think ought to be enforced for 

 the security and convenience of the public. 



In viewing the probable causes of disappointment to the pub- 

 lic which might occur from the want of the due management of 

 this now greatly extended concern, I have been induced to make 

 very particular inquiries as to the probability of the stoppage of 

 the pipes, by which the gas is conveyed to the different parts of 

 the metropolis. The result is certainly satisfactory, as I find 

 that in the cast iron pipes or mains not the smallest deposit or 

 corrosion takes place ; there is, however, a very considerable 

 tendency to stoppage in the service pipes, which are made of 

 wrought iron, insomuch, that many of these pipes have been 

 found completely choaked up in four or five years use. 



The pipes, also, in the interior of the shops and houses, and 

 for the immediate conveyance of the gas to the lamps, which 

 pipes are generally made of copper, are liable to stoppage by 

 internal corrosion. The wrought iron service pipes may, how- 

 ever, be conveniently replaced by lead, which is not subject to 

 this deposit, and the copper pipes by those of block tin, both 

 of which have been so used with good effect. 



It is satisfactory, therefore, to observe, that that which would 

 be a general and extensive evil (if there existed any liability of 

 stoppage in the mains), has no existence at all, while that which 

 is comparatively a less evil, being merely partial, may be easily 



• Probably from the experiment having been made on a larger scale than any before 

 tried. 



