APPENDIX 



CONTAINING 



SOME ADDITIONAL REMARKS 



ON 



HEAT, COLD, AND LIGHT. 



J HERE is but little probability of our arriving at 

 any great degree of accuracy in our opinions con- 

 cerning these subjects, if in our reasonings upon 

 them we only consider them separately j for there 

 are several cases in which they have a dependence 

 upon each other, which can only be tracrd out by 

 considering them together. To answer this pur- 

 pose, the following pages are written. 



As in the course of our discussion, the degrees 

 of heat and cold will be spoken of, it appears ne- 

 cessary to premise a little with regard to the instru- 

 ment by which they are. usually (though not always) 

 measured. This instrument is called a thermo- 

 meter : to describe it with a nice particularity is not 

 requisite, since more may be learnt from five 

 minutes' examination of one, than could be ga- 

 thered from a description which micht fill half a 

 dozen pages. In order that thermometers of dif- 

 ferent sizes may produce exactly the same conr 

 chmon in determining the heat or cold of bodies 



applied 



