INTROBUCTIOK* JX 



fhat of Winter is, that in fummer the rays of the fun 

 fall more perpendicularly, and pafs through a lefs 

 denfe or lefs thick part of the atniofphere; and, 

 therefore, fall with greater force and in greater num- 

 ber on the fame place : And befides, by their long 

 continuance, a much greater degree of heat is im^ 

 parted by day, than flies off by night. 



" A regiment, which had been abroad at Cartha- 

 gena and Jamaica, was afterwards ordered into th-e 

 Highlands of Scotland ; and on one day in particu- 

 lar, as they were on their march in the Highlandsj, 

 it was agreed by the officers and all the men, that 

 they had never felt the heat fo intolerable in the 

 Weft Indies */' 



Suddien -changes from heat to cold, and from cold 

 to heat, make either feel greater than they really are : 

 In fummer, if you put your hand into a good fpriaig 

 or well, you cannot with eafe hold it long, on account 

 of cold; and in the winter, the fame fpring feels 

 warm, although the water of it be of the fame degree 

 of heat as it was in fummer. Again, if in fummer 

 you go into a cellar under ground, the air feels cold ; 

 but if you go into it in the winter, the air feels warm, 

 although its heat be nearly the fame at both timer,: 

 And in winter, when the open air is about freezings 

 if you go into a hot-houfe of about 6^ or 70 degrees 

 •f heat, it feels very warm. Hence we may infer, that 

 perhaps though the regiment thought the heat of the 

 Highlands in Scotland more intolerable than that of 

 Carthagena; yet, in fad, the heat of the Hlgh- 



* Jooe»'* Ph^ioiogical Difquifitions, p. 267. 



