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



obtained. The one in question has been in use for nearly 

 three j'ears, j'et, though it was to be apprehended, no symptom 

 of furring has taken place in the pipes. This arises from the 

 formation of the apparatus causing the matter to be deposited 

 in those parts of the cylinder where there is no current. In 

 instances where boiling water or steam is required, and where 

 the liabilit}' to fur would be consequently greater, any deposit 

 might be easily drawn off at intervals, by placing a cock at 

 the bottom of the cylinder, which however does not seem to 

 be at all requisite in the apparatus for heating the bath. It 

 may be observed, that the spiral pipe should be at least an 

 inch from the cylinder, so as to allow a complete draught be- 

 tween them. 



In instances that admit of the bath being above or on the 

 same level with the apparatus, the following will be found to 

 be a very simple mode, and obviates the inconvenience of at- 

 tention to the opening and shutting of the cock f as above 

 described, the fire being all that it is necessary to attend to 



in this instance. The pipes b and d are made to communicate 

 with the bath, which should be filled, previously to lighting 

 the fire, to a level above the pipe d. 



From the tendency of heat to preserve an equiUbrium, as 

 the water becomes heated in the cylinder it will immediately 

 flow into the bath, and its place is supplied by cold water ; thus 

 forming a continual current until the whole is heated to the 

 required temperature, when the cocks f and g may be shut. 

 In order to prevent any injury to tlie boiler fi'om the evapo- 

 ration of the water after the cock g is shut ; the pipe b may 

 be extended to the cistern as in the apparatus first described, 

 and by means of a double way cock at g, when the communi- 

 cation with the bath is cut off, it would be opened with the 

 cistern, and vice versa. 



In this arrangement the first-mentioned mode of heating 

 the bath might be adopted if desired. In both cases the safety- 

 pipe e is, of course, equally requisite. 



XXIV. On 



