AMERICAN INSTITUTE. 513 



of New-York do, at all seasons of the year; the heat of mankind 

 is always the same, whatever type or race they belong to, and 

 whether old or young, Hindoo, African, American, or European, 

 rice eater, or beef eater. 



It is impossible to estimate heat by the touch; if on entering a 

 room, you place your hand on a marble mantelpiece, it feels cool, 

 and immediately afterwards on a velvet curtain, it feels warm, 

 still they are both precisely of the same temperature, every article 

 in the room, whether stone, wood or iron, if tested by the ther- 

 mometer, would be found of the same degree of heat. In summer 

 you throw off your flannel, and put on a thin cotton or linen shirt, 

 and consider yourself much cooler — this is an error, because flannel 

 is a worse conductor than cotton or linen. If you wish to pre- 

 serve ice, you cover it with flannel, and it retards the approach of 

 heat; were you to use linen, it would melt at once. 



I have heard men say, that in winter they wear black cloth 

 coats, because black is a conductor of heat; this is true as long 

 as they remain in the sun, but they are cooler the moment they 

 enter the shade. The nearer we approach the sun the colder we 

 become, as may be proved under the equator, where the high 

 mountains are covered with eternal and never melting ice. The 

 sunbeams in bringing heat and light to the earth, pass through 

 an atmosphere hundreds of degrees below zero; still the mean 

 temperature of any place, varies less than a degree, notwithstand- 

 ing, the winter may be intensely cold, and the summer equally 

 hot. All parts of the world have an average climate. All man- 

 kind are hourly changing, notwithstanding the form of each finger 

 nail and scar are apparently as they were in our infancy, still an 

 invisible change takes place of which we are entirely unconscious; 

 every hour a small portion is carried away, and its place supplied. 

 And thus our arms, legs, and bodies, are consigned to the dust, 

 every five or six years, and become what — manure, which enriches 

 a plant, that forms a flower, to feed an animal, whose flesh we 

 eat, and thus during our lives, we may eat ourselves, over and 

 over again. Atmospheric air, which during respiration we draw 

 into our lungs, contains two gallons of carbonic acid gas, in every 



[Am. Inst.] 33 



