LECTURE XXVI. 



CHEMISTRY. 



THE CHEMICAL EFFECTS OF CALORIC ; EXPAN- 

 SION, FUSION, FLUIDITY, VAPOUR, AND COM- 

 BUSTION. 



IT was necessary in the last lecture to give a 

 general view of the properties of caloric. I fear 

 I shall be thought in the present to be guilty of 

 something like repetition ; but it is necessary to 

 the understanding of the effects of caloric as an 

 agent in chemistry, to call your attention at 

 present to the subject rather more in detail. 



1st. The presence of caloric EXPANDS all bo- 

 dies. 



There are three forms under which matter 

 can appear. 



The first comprehends solid bodies, as iron, 

 &c. ; the second, unelastic or incompressible fluid 

 bodies, as water, oil, spirit of wine, &c.; the 

 third, elastic compressible fluids, as air. I shall 

 now show the effects of caloric in expanding all 

 these. If an iron or brass wire of about a quarter 

 of an inch in thickness is cut so as when cold to 

 fall just withinside, or short of two rings made to 

 receive it, by rubbing it very hard with your 

 hands or a piece of cloth it will be made warm ; 

 H will consequently be expanded, and lengthened 



D 5 



