S48 History of Mechanical Inventions and 



required even once a day when G does not exceed six or eight 

 feet perpendicular height, and the water in A is not suffered 

 to boil violently. I know, experimentally, that when G is 

 about four feet high, the water circulates more than a week 

 in a Thermosiphon 2\ inches diameter, (erected in a green- 

 house under my superintendence,) without the least occasion 

 to fill it, although the water in A is often boiling. But it 

 ■would be advisable never to let the temperature of common 

 -water exceed 208° or 210°. For low elevations of G, and for 

 heights of from fifteen to twenty feet, 160° to 180° in the 

 boiler, is as much as the machine will well bear when common 

 water is used, unless it has caloric rapidly extracted from its 

 upper part : this will condense the steam which may arise. The 

 highest useful temperatures of fluids for particular elevations 

 can only be ascertained by experience and attention. 



The boiler should have a recess in its side to receive the 

 end of the tube. This recess may project several inches, ac- 

 cording to the size of the tube, from the body of the boiler, 

 so as not to be immediately subject to the action of the fire. 

 ' The fluid in this part will not be much agitated by ebullition 

 in the boiler, but will ascend tranquilly into the machine, and 

 take but few air or steam bubbles with it. 



Mr Fowler then shows how this contrivance may be applied 

 for heating fluids for dyeing, hat-making, washing, heating a 

 bath, heating a hot plate for copper-plate printers, making in- 

 fusions of malt, heating hot-houses, green-houses, aiid conserva- 

 tories, ?i eating the fronts of garden and other ivalls, S^c. <^c. 



The method of applying it to heating a bath is shown in 

 Plate III. Fig. 9, where A is an open vessel two-thirds full of 

 water, placed on the kitchen fire. I is the ascending leg of 

 the Thermosiphon. W is the bath, with a double casing at 

 the back and bottom. J J is the descending leg ; and G being 

 the highest point of the Thermosiphon, it will be seen that the 

 bath which in this case is the object to be heated, is situated 

 between the highest point and the lowest, which is the coldest 

 part of the descending leg of the Thermosiphon. V is one 

 of the inner walls of the house ; and, as the Thermosiphon 

 ■ may be of almost any shape, however tortuous, of course the 



