36 LEADING AMERICAN MEN OF SCIENCE 



are better rusted. Steam-pipes used for heating rooms should be 

 painted or covered with paper. 



He then considers the question of why negroes are black and 

 arctic animals white, and goes so far in these speculations as to 

 lose sight of his own experiments which proved that color made 

 no practical difference in the radiation and absorption of heat. 



"All I will venture to say on the subject is, that were I called 

 to inhabit a very hot country, nothing should prevent me from 

 making the experiment of blackening my skin, or at least wearing 

 a black shirt in the shade and especially at night, in order to find 

 out, if by those means, I could not continue to make myself more 

 comfortable." 



Nothing in fact did prevent him, not the criticisms of his friends, 

 the remonstrances of his wife or the jeers of the street gamins, 

 from wearing a complete suit of white clothes from hat to shoes, 

 on Paris streets as a demonstration of their superiority over black 

 clothing. 



Rumford says he considers his researches on clothing "by far 

 the most fortunate and the most important I ever made," because 

 they contribute to health and comfort of life. With this practical 

 object in view, he devoted many years to experiments on the propa- 

 gations of heat through solids, liquids and gases, and attained 

 very clear ideas of the three ways in which heat travels, by direct 

 radiation, by conduction from particle to particle, and by convec- 

 tion or currents of heated particles. These experiments were 

 made by thermometers with the bulb sealed into the center of a 

 large glass bulb. The space between the outer bulb and the ther- 

 mometer of two of these instruments being filled with the sub- 

 stances to be compared, they were taken from boiling water and 

 plunged into ice-cold water or vice versa, and the rate of change 

 of the thermometer noted. In this way he determined that moist 

 air is a better conductor of heat than dry. Thus he explains 

 "why the thermometer is not always a just measure of the ap- 

 parent or sensible heat of the atmosphere," and why colds prevail 

 during autumnal rains and spring thaws, and why it is so danger- 

 ous to sleep in damp beds and live in damp houses, and he takes 



