308 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



of the burning elements is effected. If this is so, there can be no doubt of 

 its utilit}'. In the ordinary combustion ot fuel, it is ascertained that a 

 large proportion of the oxyg-en of the air escapes uncombined. If the use 

 of steam will facilitate the utilizing of this oxygen, it would be a decided 

 advantage. This was the only light in which he could view any benefit 

 arising from the use of the vapor of water in connection with fuel. 



Mr. Dibben thought the amount of uncombined oxygen wliich escaped 

 up the chimney was not g-rcat; according to chemical tests made with the 

 waste products of melting-furnaces, it is shown that only five or six per 

 cent, of the oxygen thus escapes. 



Mr. Root remarked that the escape of uncombined oxygen is much greater 

 from the fires which heat boilers than from furnaces. 



Dr. Rowell drew a diagram of the furnaces used for burning wet tan- 

 bark, which he had seen in operation during the last week. When the 

 furnaces were first put up iron grate bars were used; but they were soon 

 warped so as to be useless. The grates are now made of fire-brick. The 

 ovens are about four feet wide and eight feet long; the fire is first started 

 with, wood, and the whole interior is made nearly red hot before the spent 

 tan is putin , The flame is conducted from this oven through a passage- 

 way under the boiler; There seemed to be no great draft, as proved by 

 holding the hand before the damper, but he accounted for this by a con- 

 densation of vapor in the chimney. There is probably two or three per 

 cent, of the tan that is not burned. The same quantity of fire made of coal 

 would have produced a great draft. 



Mr. Bartlett said the vocation of water in combination with fuel was to 

 expose a fresh surface of coal to the action of oxygen; there was no chem- 

 ical action whatever. We find that dry tan, through which the air very 

 slowly permeates, makes a smoldering fire, but not a bright one. In burn- 

 ing tar, at Old City, the furnaces are two feet long and one foot wide, but 

 the smooth surface of the tar prevents it from burning fast; therefore water 

 is put into it, which causes the tar to bubble, and in this way a greater 

 surface is exposed to the action of oxygen in the process of combustion. 

 So when a jet of steam is let into a mass of coal in a furnace it loosens the 

 pellicles of the coal and agitates the mass generally; but in all these cases 

 there is a greater quantity of fuel consumed, and therefore a greater heat 

 is produced in the same furnace than there would be without the use of 

 steam. 



Mr. Stetson read from Prof. Renwick's work on the Steam Engine ia 

 i-elation to the advantages claimed by water in the ash-pan of a boiler 

 furnace. 



Mr. Mather remarked that in some potteries in England it was the inva- 

 "riable rule to use a certain quantity of water along with the coal, while in 

 Vermont, where wood is burned in potteries, they went to the other extreme 

 and would never use green wood. 



Prof. Joy stated that some sixty patents had been issued within the last 

 forty years for burning water and decomposing water for the purpose of 

 making illuminating gas — an able pamphlet on the subject had been pre- 

 pared for the Manhattan Gas Company of this city by Mr. Henry Watts. 



