294 An Invention for preserving the Lives 



neral, connected with their application as sources of light, 

 consists in the quantity of sulphureted hydrogen gas, which 

 is mixed with their aeriform products ; and it unfortunately 

 happens that the coal, otherwise best adapted to this pur- 

 pose, yields generally the largest proportion of this offensive 

 gas. The only effectual method of purifying the coal gas 

 from sulphureted hydrogen, on the large scale of manufac- 

 ture, will probably bq found to consist in agitation with, 

 quicklime and water, composing a mixture of the consis- 

 tence of cream. Simple washing with water by no means 

 effects the complete separation. 



In the experiments which were made on the products of 

 the distillation of coal, T purposely neglected the amount 

 and analysis of the condensible fluids, because they cannot 

 be advantageously ascertained by the same operation with 

 the elastic ones. They may also be much better determined 

 on the large scale of manufacture, than bv limited experi- 

 ments. For the same reason I was not solicitous to mea- 

 sure even the aeriform fluids ; and on this subject, I be- 

 lieve, more accurate information has been communicated by 

 Mr. Murdoch, than it was in my power to acquire. 



XLIII. Lieutenant Bell's Invention for preserving the Lives, 

 of Mariners in Cases of Shipwreck*. 



Jl ublicity having been recently given to some experiments 

 off the eastern coast of this island, for preserving lives in 

 cases of shipwreck, by means of a rope attached to a sbeij 

 thrown from a mortar, the Society of Arts, 8cc, has thought 

 it incumbent on them to remind the public, that so far back 

 as the year 1792, a bounty of fifty guineas was given to Mr. 

 John Bell, then serjeant, afterwards lieutenant of the royal 

 regiment of artillery, for his invention of throwing a rope 

 on shore, by means of a shell from a mortar, on board the 

 vessel in distress : the particulars of which were published 

 in the tenth volume of the Society's Transactions, page 204 ; 



* From Transactions of the Society for the Encouragement of Arts, Manu- 

 factures, and Commerce, for 1807. 



but 



