AMERICAN INSTITUTE. 145 



heads, and case, all of one piece of metal, without joints uniting 

 them;" so that instead of the multitude of joints of the ordinary 

 tubular heater, there are in this no joints save the six screw plugs 

 in each section, which stop the holes when the cone was vented 

 and removed, and the ground joint where the sections are united. 



The surfaces being so subdivided as to be small in any one con- 

 tinuous direction, the metal is thin, and of uniform thickness 

 throughout; and, being homogeneous, and homologous, is sub- 

 ject to no galvanic action, irregular contraction and expansion, or 

 danger of leakage from any cause. 



The surface of cast iron, especially when cast in cores, is rough, 

 and by its points and projections presents a greater extent of sur- 

 face in actual contact with both water and steam, than would 

 wrought iron of equal nominal extent. A square foot, therefore, 

 of cast iron, is more efficient than the same extent of wrought 

 iron, or even of brass or coj3per. 



It is unnecessary to say a word upon the value of the feed 

 water heater. It is universally understood that a portion of the 

 heat which is wasting from the exhaust pipe, may be utilized so 

 as to raise the temperature of the feed water, from ordinary at- 

 mospheric temperature, say 40'^ to 70*^, up to very near the boil- 

 ing point. 



The ordinary methods of accomplishing this important saving 

 of about fifteen j^er cent, are expensive, and though many of them 

 are efficient, they are, in general very troublesome on account of 

 leakage This heater aims at, and it is believed, attains to a 

 maximum of effect and durability, at a minimum of cost and 

 trouble. 



The operation of this heater will be understood by a glance at 

 the wood cuts : Fig. I, is an outside elevation ; fig. II, is a ver- 

 tical section through the axis ; fig. Ill, is a top view of the lower 

 half, with the upper half removed at the joint, at fig. I, showing 

 the two rows of tubes, eighteen in all, viz : twelve in the outer 

 row, and six in the inner one; the screw plugs, with square heads 

 to turn them in by; the external flange, and central but, with its 

 space around the bolt for the passage of the water from the lower 

 to the upper section ; fig. IV is a section through tubes and curves, 

 on the line c d, fig. II. 



[Am. Inst.] 10 



