I 



Biographical Memoir of Count Rumford. 4 1 



The Rumford lamps are not less diffused nor less popular than the 

 chimneys and soups of the same name. This is a true character of a 

 good invention. 



He determined, by physical experiments, the rules that render the 

 oppositions of color agreeable. Few fine ladies imagine the choice 

 of a border, or of the embroidery of a ribbon, depends on the im- 

 mutable laws of Nature, and yet such is the fact. When one looks 

 steadily for some time at a spot of a certain color on a white ground, 

 it appears bordered with a different color, which, however, is always 

 the same with relation to that of the spot. This is what is called the 

 complementary color; and, for reasons which it were needless to de- 

 velops here, the same two colors are always complementary to eacl 

 other. It is by arranging them that harmony is produced, and the 

 eye flattered in the most agreeable manner. Count Rumford who 

 did every thing by method, disposed, according to this rule, the colors 

 of his furniture, and the pleasing effect of the whole was remarked 

 by all who entered his apartments. 



Continually struck, in all his labors, by the wonderful phenomena 

 of heat and light, it was natural for him to attempt a general theory 

 respecting these two great agents of nature. He considered them 

 both as only effects of a vibratory motion impressed on the molecules 

 of bodies, and he found a proof of this in the continual production 

 of heat which takes place by friction. The boring of a brass gun, 

 for example, putting water in a short time into a state of ebullition, 

 and this ebullition lasting as long as the motion which produced it, 

 he found it difficult to conceive how, iif such a case, matter was dis- 

 gaged, for it would require to be inexhaustible. 

 ■ He moreover proved, better than any person, that heat has no 

 weight. A phial of spirit of wine, and another of water, remained 

 in equilibrium after the congelation of the latter, although it had lost 

 by this, caloric enough to raise the same weight of gold to a whit< 



heat. 



He invented two singularly ingenious instruments. The one, 



which is a new Calorimeter, serves to measure the quantity of heat 

 produced by the combustion of a body. It is a box filled with a 

 given quantity of water, through which the product of the combus- 

 tion is made to pass by a serpentine tube ; and the heat of this pro- 

 duct transmitted to the water, raises it a determinate number of de 

 grees, which serves as a basis to the calculations. The manner i 

 which he prevents (he external heal from altering bis experiment, 



Vol. XIX.— No. 1. 6 





