EXPERIMENTS WITH AIR FURNACES. 229 



the merits of their apparatus consist in a multiplic- 

 ity of tubes, " return drafts," flues, chambers, damp- 

 ers, etc. They are for the most part as intricate 

 as Mrs. Chauncey's celebrated new cooking stove, 

 which required a whole cord of wood to warm all 

 its mysterious windings and passages ; and even 

 after this expenditure of fuel, she declared she 

 could not retain heat enough in the machine to 

 bake her morning biscuit. All furnaces found in 

 the market have the radiating surfaces in the air 

 chamber constructed mainly of cast-iron. They 

 all have more or fewer joints, formed by placing to- 

 gether pieces of metal, which are filled with some 

 kind of lute or cement, when the furnace is placed 

 in position. The air is allowed to pass in beneath 

 the base, and around the ash-chamber and fire- 

 pot ; and usually the current of air is unobstructed 

 by any devices to retain it in contact with the ra- 

 diating surfaces. 



The two furnaces subjected to trial may be re- 

 garded as representative devices, and combining as 

 many good qualities as any offered for sale by 

 dealers. The first was put in position in a base- 

 ment, and arranged for warming a library, a room 

 forty feet long, twenty wide, and eleven high. It 

 was kept in place for five weeks, and its working 

 diligently attended to. With the aid of proper in- 

 struments, thermometers, hygrometers, etc., and 



