Mr. E. D. Thomson's Mode of heating Water for a Bath. 105 



faggot, did not amount to '2\d. ; but as more than usual care 

 was taken in the experiment in question, it may be more fair 

 to estimate the expense on an average at 3rf. This does not 

 include the wear and tear of the apparatus, which is, however, 

 of a very durable nature. 



I shall now proceed to describe the apparatus, and the mode 

 of using it. 



A cylinder 18 inches high and 9 inches in diameter, is sur- 

 rounded by a spiral pipe, as may be seen in the annexed 

 figure : — this pipe communicates with a cistern a, which of 

 course must be above the level of the apparatus ; — the water 

 passes from the cistern through the pipe b b into the cylinder 

 at c, and from thence through the pipe d into the bath. When 



the cock /' is opened, hot water will flow from the cylinder 

 through the pipe d into the bath, and its place will be imme- 

 diately supplied by cold water from the cistern through the 

 pipe b b, thus creating a continual current of water through 

 the boiler, which becomes heated in its passage. The degree 

 of heat may be regulated by partially opening or shutting the 

 cock f, by which means the water will flow more rapidly or 

 be longer subjected to the influence of the fire. In case of 

 the water boiling when the cock f is shut, the steam will pass 

 off" by the open pipe c, which must of course be raised above 

 the level of the cistern. The pipe being always open provides 

 in the completest manner for the safety of the apparatus. 



Various other forms of apparatus and modes of using them 

 have suggested themselves to me ; but I have thought it bet- 

 ter first to describe the one which had stood the test of actual 

 experiment, and from whicli so satisfactory a result has been 



iVtT«6Vmi-. Vol. 1. No. 2. /''(■/;. 1827. P obtained. 



