^8 On Caloric, and. the Heat evolved ^during ComtusfioH, 



cessarilv happen, as often as we have recourse to the particu- 

 lar figure of each machiiie/ in order to demonstrate a pro- 

 perty which is coninjon to it- with all others. These 

 common properties being ^hqse whiych \^e;.have,,i;x;\5icy/ in 

 this essay, it is clear that v^^# shall only succeed in fuidingj 

 ihera by the abstraction of particular forms* Let i>s begin,- 

 lherxifore,J^y;simplifyin;g the. state of, ^he.q^^^^ 

 ing to consider under one and the same system, bodies dij:- 

 fcring in. their natuiq. , Finally,, let us restore to niachines, 

 their visinertice, ^Jt^ ^\\\ j:)e^.ej\sy^ , ai^e^^,.^his,.^o ,|C^^ 

 their mass in the result : we shall have the choice of doing 

 SQ- or not; and, in setting out, the soluli9i| of the probler^ 

 T^ill be • eqvially. , geni^ral, at the same ;l|i|i)e,,tlxat it will be 

 simpler. .^a oi 



[To be continued.] 



XXX, On Caloric, and the Heat evolved during Comhisiion^^ 

 By James, Scholes, Esq,, JMctnchester. 



To Mr. rilloch. '^^"^ 



SIR, ,1, J- y,', 



xIaving been induced to pay particular attention to co^ii-; 

 bustion for some time past, i have insensibly imbibed prin- 

 ciples diffcpent iVom the generally received theory, I very 

 coon began to suspect caloric as a compound substance, and 

 six months ago had recognised two fluids of electricity for 

 its component parts. The only demonstrative grounds I then 

 had for my ideas was the production of hght and heat, parti- 

 cularly the latter, and for the purpose of measuring the quanti ty 

 thereof I had an apparatus constructed. But when Mr. Davy's 

 recent experiments were noticed in your JNIagazine, 1 im- 

 n^ediately saw them as an additional support of my peculiar 

 principles, and prepared a lecture, which was delivered to a 

 Society in this town on the 29th of January, laying down 

 the whole system, as supported by facts deduced from elec- 

 tricity and the experiments of Mr. Davy, which I intended 

 to publish when more matured ; but on looking over the 

 monthly publications yesterday, I found a communication 

 in Mr. Nicholson's to a similar purport, which has induced 



me 



