(y NEW BOILER. 



Boiler for this surface, may be more than sufficient to compensate the 



steam* 11 h^tvine ^vantage derived from the extended surface of the bottom. 



its bottom ter- And where the boiler is employed for producing steam, as 



tubes 1 " 1 ^ m ** * s indispensably necessary that it should be of a thickness 



sufficient to resist the expansive force of the steam, it is 



evident, that if the diameter be augmented (with a view to 



increase the surface of the bottom) a considerable expence 



is incurred on account of the additional strength that must 



be given to the sides. 



Having been engaged in the year 1796, in a set of ex- 

 periments, in which I employed the steam of boiling water 

 as a vehicle of heat; I had a boiler made for this purpose, 

 ■"pn a new construction, which answered well, and even 

 beyond my expectations; and, as this boiler might be used 

 with advantage in many cases, even where it is only re- 

 quired to heat liquids in an open boiler, this, and another 

 motive, which it would be useless to mention in this place, 

 have lately induced me to construct one here (at Paris) and 

 to present it to the Institute. 



The object chieily had in view in the construction of this 

 boiler, was to give it such a form, that the surface exposed, 

 to the fire should be great in comparison with its diameter 

 and capacity ; and this without having a great surface ex., 

 posed to the cold air of the atmosphere. 



The body of the boiler is in the shape of a drum. It is 

 a vertical cylinder of copper twelve inches in diameter, and 

 twelve inches high, closed at top and at bottom by circular 

 plates. 



In the centre of the upper plate there is a cylindrical 

 neck six inches in diameter, and three inches high, shut at 

 top by a plate of copper three inches in diameter and three 

 lines in thickness, fastened down by screws. 



This last plate is pierced by three holes, each about five 

 lines in diameter. The first, which is in the center of the 

 plate, receives a vertical tube, which conveys water to the 

 boiler from a reservoir which is placed above. This tube, 

 which descends in the inside of the boiler, to within an 

 jnch above the circular plate which forms its bottom, has 

 a cock near its lower end, This cock is alternately opened 



and, 



