invented hy John Roger s^ Jun., Esq. 



135 



as steep an inclination as possible, to the bottom of the boiler. 

 The supply cistern [e) must be so placed that its bottom is not 

 lower than the highest point of the pipes. The top of the steam- 

 valve (w) should be level with the top of the supply cistern. Just 

 below the valve, on the steam-pipe, may be fixed a small cock [k), 

 connected with a pipe laid into the house, by which, whenever the 

 water boils, the house may be steamed. In small apparatus this 

 will happen pretty frequently, but in large houses, in order to 

 insure this advantage, a stopcock or sluice should be placed on 

 the flow-pipe {f), by which, the circulation being intercepted, the 

 water in the boiler may at any time be raised to the boiling point 

 in a few minutes. 



Fig. 27. represents a contrivance which is not liable to any of 

 the defects of stopcocks, which impedes the circulation less than 

 any except large sluices, and which is comparatively unexpen- 

 sive. The hollow plug g {^g. 27.) is fitted with a valve, per- 

 fectly watertight. This valve is opened and shut by the handle 

 sliding through a stuffing-box in the end of the plug. By closing 

 it the gardener may at any time cause the water in the boiler to 

 boil, when, by opening the cock k^ he admits as much steam to 

 the house as may be desired. A small pewter pipe fin. diameter 

 is sufficiently laige to conduct steam into the house, and its 

 flexibility renders it very convenient. Where this arrangement 

 is adopted, the supply cistern must be larger than is otherwise 

 necessary, and should contain 10 or 12 gallons. The steam-pipe, 

 also, should be placed on the top of the boiler, and be of sufficient 

 diameter to allow the water and steam to separate, that the 

 former may not be blown out through the pipe along with the 

 steam; and the valve should be loaded with a few ounces of lead. 



Fig. 28. exhibits the apparatus, with the addition of a re- 

 servoir ; this in small pits is very desirable, and I have always 



