190 THE FIBS-DAMP'S FAMILY CIRCLE. 



siderably before the epoch when it is usually understood that 

 the discovery of the individual existence of separate gases was 

 made by Cavendish, Priestley, and Lavoisier, the student of 

 fire-damp will find scattered about some curious information 

 on this subject. Amongst other things of this kind, it will 

 be easy to prove by satisfactory evidence that the discovery 

 of hydrogen gas ought no longer to be attributed exclusively 

 to Cavendish, but partly to Mr. John Maud, in the year 

 1733. The circumstances of the discovery were as follow : 



The colliers of Sir James Louther, in sinking a pit near 

 Whitehaven, came upon a blower of fire-damp, which, after 

 giving some annoyance, was finally disposed of by conveying 

 it to the surface through a pipe, and there allowing it to 

 escape. An undiminished jet of gas continued to be liberated 

 from this pipe for several years, and was made subservient 

 to some investigations on the nature of fire-damp before the 

 Royal Society. 



The experiments were conducted by means of gas which 

 had been collected in a bladder, and they have the collateral 

 interest of drawing attention to what was long supposed to 

 be a fact namely, that the sparks of flint and steel would 

 not ignite mixtures of coal-mine inflammable gas and atmo- 

 spheric air (fire-damp) ; ' for which reason,' states the narra- 

 tive, ( it is frequent to use flint and steel in places affected 

 with this sort of damp, which will give a glimmering light 

 that is a great help to the workmen in difficult cases.' 



Here we have then the origin of the steel-mill, the sparks 

 of which were considered to be totally incapable of igniting 

 fire-damp until the year 1783, when the fallacy of the opinion 

 was demonstrated by an explosion at the Wallsend colliery. 

 The experiments performed at the Royal Society on actual 

 fire-damp gas were followed by others still more interesting ; 

 involving, as we shall presently see, the discovery of hydrogen. 



Mr. John Maud, having been led by theoretical con- 

 siderations to assume that fire-damp was of a sulphureous 



