HEAT, COLD, AN 7 D LIGHT. 32.T 



and air, are non-conductors of Heat : indeed, he 

 thinks it essential to all fluids, that they should be 



non- conductors 



my young readers may have an idea of the advantages which 

 aiay arise, from applying philosophical- principles to seh 

 purposes, I present them with the following extracts : 



In Essay VI. the Count says, " Among all the various 

 " substances of which coverings may be formed for confining" 

 " Heat none can be applied with greater advantage than at- 

 " mospheric air. It is what Nature employs for that purpose ; 

 " and we cannot do better than imitate her. 



" The warmth of tke wool and fur of beasts, and of the fea- 

 " thers of birds, is undoubtedly owing to the air in their in- 

 " terstices ; which air, being strongly attracted by these 

 " substances, is confined, and forms a barrier, which not only 

 " prevents the cold winds from approaching the body of th 

 " animal, but which opposes an almost insurmountable ob- 

 " stacle to the escape of the Heat of the animalinto the at- 

 " mosphere. And in the same manner, the air in snow serves 

 u to preserve the Heat of the earth in wioter. The warmth, 

 44 of all kinds of artificial clothing may be shewn to depend 

 " on the same cause ; and were this circumstance more ge- 

 " nerally known, and more attended to, very important im- 

 " provemeuts in the management of Heat could not fail to 

 " result from it. A great part of our lives is spent in guard- 

 " ing against the extremes of Heat and of Cold, and in ope- 

 " rations in which the use of Fire is indispensable ; and yet 

 " how little progress has been made in that most useful and 

 " most important of the Arts the management of Heat! 



" Double windows have been in use many years in most of 

 " the northern parts of Europe, and their great utility, in 

 * rendering the houses furnished with them warm and com- 

 " fortable in winter, is universally acknowledged, but I 

 " have never heard that any body has thought of employing 

 l< them in hot countries to keep their apartments cool in sum- 

 " mer; yet how easy and natural is this application of so 

 "simple and so useful an invention! If a double window 

 " can prevent the Heat which is in a room from passing out. 



