496 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Leather Shoes with Wooden Soles. 



Mr. George May Powell exhibited a pair of leather shoes, 

 having wooden soles, made in this city. The best feature was 

 their dryness; they were well adapted to muddy streets. 



Mr. T. D. Stetson said these shoes reminded him of what he 

 saw on the other side of the Atlantic. He was surprised to find 

 so many people Avearing wooden shoes in the North of England. 

 It seemed to him they could be heard a quarter of a mile otf 

 when walking on floors or pavements. 



Mr. Maddock remarked that it was customary in England to 

 partly cover the wooden shoe with leather; a wooden sole with a 

 leather upper was quite common. 



The chairman said the shoe now exhibited is ver}'- different 

 from the wooden shoe or the leather shoe with wooden sole worn in 

 England. It will be observed that this is like an ordinary leather 

 shoe, with two additions of wood, namely: a wooden heal and a 

 wooden tap. This arrangement allows the sole to bend as the 

 foot bends. It is light, and it appears to be useful for farm hands 

 who have to pass over plowed ground. A shoe with a thick 

 sole is preferable to an India rubber shoe, covering one of leather. 

 Some time ago India rubber boots were worn, but it was found 

 they kept the feet continually moist from their perspiration. 

 India rubber overshoes are now made with ribs or creases inside, 

 which allow the perspiration to pass off. As many persons will 

 wear thin shoes and boots, the rubber overshoe is best adapted 

 for their use. 



Ventilation. 

 The selected subject was brought up by the Chairman, who said 

 that all attempts to carry ofl' certain portions of the air of a room, 

 which were supposed to contain vitiated air, were founded on a 

 wrong impression regarding the separation of gases by their dif- 

 ferent densities. In this ease, the law of diffusion Avas superior 

 to the law of gravity — hydrogen will not remain at the top, and 

 carbonic acid at the bottom of a room. The molecules of the 

 same gas are constantly repelled. The q^irbonic acid gas rises, 

 and the hydrogen descends, until they are equally distributed ; 

 but the hydrogen is diffused five times as fast as the carbonic acid. 

 Th^ rapidity with which gases intermingle, is inversely as the 

 square root of their densities. Carbonic acid may be poured from 

 one glass into another, because it ie heavier than common air, but 



