. ic-4 Scnj'ulicn a bad Meafure of Temperature. [Book II. 



to a hand which is of a lower temperature *. Tra- 

 vellers, therefore, from a warm to a cold country, 

 \vill have lenfations very different from thofe who tra- 

 vel in an oppofite direction, mould they happen to 

 meet, as they frequently do, in a temperate climate. 

 It is evident that the travellers from a cold climate, 

 being deprived of lefs heat than ufual, will have the 

 fenfation of warmth ; and the others, on the contrary, 

 will experience a degree of cold iufficient to excite 

 confiderable uneafinefs. 



jdly. The matter of fire wil'Iexift in a (late of com- 

 bination. I do not contend for the term chemical 

 combination, in the ftrict and literal fenfe of the word ; 

 it is fnfficient if it can be proved, that caloric may exift 

 in bodies in a latent ftate, or in a ftate not perceptible 

 to our fenfes. It will be found by obfervation, that 

 every body which exifts contains a quantity of the 

 matter of fire in this fixed or neutralized ftate, diiarm- 

 ed of all its active, penetrating, and deftruftive quali- 

 ties, like an acid and an alkali in combination. If 

 the coldeft bodies with which we are acquainted are 

 condenfed or brought into a fmaller compafs, a quan- 

 tity of caloric will be emitted. If a piece of lead or 

 iron is beaten with a hammer, or compreiTed in a vice, 

 fo as to force it to contract its dimenfions, it has been 

 already remarked that a degree of fenfible heat will 

 i>e produced. 



Fluids, from their very nature and conflitutios, con- 

 tain a greater quantity of caloric in a latent ftate than 

 . folid bodies : indeed it is now univerfally admitted, 

 and may be eafily proved, that the fluidity of all bo- 

 dies is altogether owing to the quantity of fire which 

 they retain in this latent or combined ftate, the elafti- 



* Crawford on Animal Heat, p. 5. zd, edit. 



city 



