CHEMICAL THEOKY. J77 



Secunde.— If the iiglit were afforded by tlic oxigen gas we Dissert atin on 

 riAOuld have most when the greatest quantity of oxigen disap- effects of ^heat 

 'oeais ; but th(? light is greater in tlie combustion of phosphorus, Heiht and com- 

 '.han ip that of clxarcoal, and still greater than in the combus- °^^ '""' 

 :iou of hydrogen gas; bat more oxigen gas disappears in the 

 ^orpbustion of the hydrogen gas than in the other two. We 

 have no accurate photometer by which we can measure the 

 , ^nten^ity of li^h-*^, and even granting that 1000 times as muck 

 light appeared in the combustion of phosphorus as in that of 

 hydrogen gas, no one can affirm that the light on inflammation 

 docs' not bear a ratio with the intensity of heat, and wi? 

 find that the heat evolved in the inflammation of hydrogen 

 _gas is hut sma^l when compared to that of phospliorus or 

 charcoal, If-'ght docs not appear iVorn the extremities of 

 die galvanic pile, unless they be connected, ^id the heat 

 aTid light conjoined. TIence we iind the greater is the in- 

 tensity of the heat in combustion, so also the light is in- 

 creased in the same proportion. 



Ter^eu.— By llie combustion of hydrogen gas and oxigen gas 

 «&;('m the new invented blow-pipe, we obtain a more intense 

 heat than could have been done before, except by mirrors 

 or Iqnses, but we observe but little light in this case. The 

 heat produced from this blow-pipe is by no mieans so in^ 

 .tei)se as many have supposed. Its effect are tried upon in- 

 flammable substances, iron, copper, and which are tbem- 

 sclvea combinations of considered heat ; in these cases therefore 

 we have i!ie heat of the hydrogen gas, and that of the inflam- 

 mable substance, acting together, and must consequently have 

 very great heat. ] believe, that fey passing a stream of oxigen 

 -^as through the flame of spirit of wine or oil, the heat 

 might be as great or greater. I have observed the action 

 of the common blow-pipe qfi a stick, of glass, and it ap- 

 peared nearly as great as that of the hydrogen and oxigen 

 gas blow-pipe : quite so great for the reasons before mention- 

 ed, it could not be. 



These, I believe, are the three principal objections whicji 

 hr.ve been stated against the doctrine which it is here at- 

 tempted to support. It would take up too long a time to men- 

 tion all which are to be met with in authors. 



Vol. Xr/.— JuN-E, ISOt). A a With 



