ARTIFICIAL HEAT AND APPAKATUS. 



47 



opposite currents are subject to check the even flow of the 

 smoke, and drive it back. 



The Pohnaise method of heating is a pLan tliat origin- 

 ated with a Mr. Murray, of Pohnaise, in Scotland, and, like 

 many other ingenious contrivances, was the result of pecu- 

 liar necessity. At the time of its introduction, it caused a 

 great furor amongst the seekers after novelties, and like 

 the fugacious follies of such persons, it soon fell into dis- 

 repute with all, excepting those who were determined not 

 to acknowledge their error. To say the best we can in 

 its favor, it is only a modified flue. The principle, if so it 

 may be called, consists in having a hot air chamber over 

 and outside the furnace, and conducting the heat therein 

 generated through one or more apertures into the house at 

 one end, and at the other having a hole level with the 

 floor, which forms the top of a drain that is conducted 

 along under ground to the furnace, and which supplies the 

 fire with fresh air to support combustion. By these means 

 the heat from the chamber is drawn through the house, 

 and a partial current produced, and from this it was at 

 first predicted that a great benefit would arise, on account 

 of the near imitation to nature's invigorating breezes. If 

 glars was not a rapid conductor of heat, this plausible 



theory might have 

 been a practical 

 good ; but as it is, 

 and as heat will 

 ascend, in opposi- 

 tion to such a weak 

 power to repress 

 it, a great portion 

 flows along at the 

 top and back })art 

 of the houiie, lea v. 



Fig. 13. 



