CHAP. 



THE ART OF WARMING. 



335 



the art of warming, which consisted in placing the fire under cover in 

 the primitive habitation, at first in caverns, but afterwards in huts of 

 wood, branches, or stone. 



F[o. 228. A Spanish brasero. 



What length of time elapsed before the invention of chimneys ? 

 Many centuries, no dotfbt ; and the smoke escaped from the hut, 

 either by the single opening which served at once for doorway and 



FKJ. 2i'9. A Roman fooulus. 



window, or, as among the Gauls, the Germans, and even now among 

 the Esquimaux and a score of other semi-savage tribes, by a hole 

 made in the upper part of the roof. 



