"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, of wearing a black shirt, in the shade, and especially at night, in order to find out if, by those means, I could contrive to make myself more comfortable." In his experiments on the conduction of heat, Rumford employed a cylinder with one end immersed in boiling water and the other in melting ice, and determined the temperature at different points in the length of the cylinder. He found the difficulty which has recently been forcibly pointed out by Sir Wm. Thomson, in the article "Heat," in the "Encyclopaedia Britannica," viz. that the circulation of the water was not sufficiently rapid to keep the temperature of the layer in contact with the metal the same as that of the rest of the water; and he also called attention to the arbitrary character of thermometer-scales, and recommended that more attention should be given to the scale of the air thermometer. It was in his visit to Edinburgh, in 1800, that, in company with some of the university professors, the count conducted some experiments in the university laboratory on the apparent radiation of cold. Rumford's views respecting _frigorific rays_ have not been generally accepted, and Prevost's theory of exchanges completely explains the apparent radiation of cold without supposing that cold is anything else than the mere absence of heat. We must pass over Rumford's papers on the use of steam as a vehicle of heat, on new boilers and stoves for the purpose of economizing fuel, and all the papers bearing on the nutritive value of different foods. The calorimeter with which he determined the amount of heat generated by the combustion, and the latent heat of evaporation, of various bodies has been already alluded to. Of the four volumes of Rumford's works published by the American Academy of Arts and Sciences, the third is taken up entirely with descriptions of fireplaces and of cooking utensils.