'13^ TRANSACTIONS OF THE 



matter which all coals contain, which we will assume to be twenty per ceot of 

 their heating or evaporating power. To burn these gases, great heat, and a free 

 supply of oxygen are necessary. In the ordinary mode of feeding upon the top^ 

 these conditions can only partially concur. In supplying the raw coal, it is neces^ 

 sarily thrown with considerable force upon the ignited mass, packing it to a greater 

 or less extent, thereby cutting off the free supply of air. Just in proportion as 

 this is shut off, is combustion imperfect. In supplying raw coal in any manner to 

 a fire, the first process is a distillation of its gases. The carbon, which may be 

 said to form the basis of the coal, cannot be brought into a high state of combus- 

 tion till these are completely expelled. The fact may be familiarly illustrated by 

 reference to the experience of any person who uses a furnace in warming his house 

 On the supply of new coal, a free draft must be allowed through the smoke-pipe, 

 or the inmates will almost instantly be choked with coal gas. Very little heat 

 results, or in other words, only partial combustion takes place till the gases are 

 expelled. This is not thoroughly accomplished till the whole mass is brought to 

 a white heat. The draft may be then shut or checked with impunity. 



The gases thrown off, and which are so offensive when allowed to find their way 

 into the house, are well known to be highly combustible. Could they be burnt, 

 or, to state the process in a different manner, could they be decomposed into their 

 constituents, and allowed to form new combinations, they would be not only 

 innocuous, but the whole power of the coal would be utilized. Thi.^ statement, 

 however, does not express the entire loss irom the no/i-consumption of the gases. 

 The process of distillation or evaporization is well known to be the most cooling 

 in nature, as any one can readily demonstrate by dropping a little ether into his 

 open hand. The first duty the fire beneath the raw coal is called upon to perform, 

 is to distil it. The next, to expel the product in vapor. These duties consume a 

 certain portion of the effective power of coal fed in the ordinary manner, and 

 diverts so much from the object to which it is directed. 



Now it is alleged that this waste might, to a considerable extent, be saved, if 

 coal could be supplied to a fire from beneath. By this process, the grate would be 

 kept clean, and allow the free passage of air. The gases evolved would ascend 

 with the air, through the super-incumbent mass of intensely ignited carbon, and 

 the conditions requisite to the perfect combustion of the gases — a high degree of 

 heat and an abundant supply of oxygen — would meet. They are fully supplied 

 by Mr. Delano's improvement, as a slight inspection of its working demonstrates. 

 Assuming, therefore, that he does accomplish the result claimed, a result better 

 by 20 or 30 per cent than the ordinary one of feeding upon, instead of underneath, 

 the burning mass, is secured. In the old process, constant attention and labor is 

 required to keep the grate bars and fire sufBciently clean to allow combustion to 

 proceed at all. In puddling furnaces and in steamships, the fire has to be drawn 

 every given number of hours, for the purpose of removing the cinders and earthy 

 matter that have accumulated. All the incombustible matter the coal contains, 

 settles upon the grate, and unless removed, would soon form a compact and imper- 

 vious bed. But by feeding from beneath, all this foreign matter very soon ascends 

 to the surface of the fire, whence it is drawn. The body of the fire never has an 

 amount of cinder or ashes mixed with it, suflScient to check free combustion. 



[-<^ bronze medal awarded. 



