Biographical Memoir of Count Rumford. 223 



but rather upon the vivacities of the combustion. By combining 

 these two observations, he invented a lamp with several paral- 

 lel wicks, the flames of which, mutually exciting each other, 

 without allowing any of the rays to be lost, are capable of pro- 

 ducing an unlimited mass of light. It is said, that when it was 

 lighted at Auteuil, it so dazzled the lamp-maker who had con- 

 structed it, that the poor man was unable to find his way home, 

 and was obliged to pass the night in the wood of Boulogne. 



I deem it superfluous to mention how he varied and adapted 

 to all sorts of uses the different instruments that are employed 

 for lighting. The Rumford lamps are not less diff'used nor less 

 popular than the chimneys and soups of the same name. This 

 is the true character of a good invention. 



He determined, by physical experiments, the rules that ren- 

 der the oppositions of colour agreeable. Few fine ladies imagine 

 that the choice of a border, or of the embroidery of a ribbon, 

 depends on the immutable laws of Nature, and yet such is the 

 fact. When one looks steadily for some time at a spot of a 

 certain colour on a white ground, it appears bordered with a 

 different colour, which, however, is always the same with rela- 

 tion to that of the spot. This is what is called the complemen- 

 tary colour; and, for reasons which it were needless to develope 

 here, the same two colours are always complementary to each 

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

 the eye flattered in the most agreeable manner. Count Rum- 

 ford, who did every thing by method, disposed, according to 

 this rule, the colours of his furniture, and the pleasing effect of 

 the whole was remarked by all who entered his apartments. 



Continually struck, in all his labours, by the wonderful phe- 

 nomena 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 impres- 

 sed on the molecules of bodies, and he found a proof of this 

 in the continual production of heat which takes place by friction. 

 The firing 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 con- 

 ceive how, in such a case, matter was disengaged, for it would 

 require to be inexhaustible. 



