APPARATUS yOR RAISING WATER IN WORM TUBS. 217 



and on a worm tub of a confiderable fize. Indeed it was ray 

 ■firlt intention to have made the worm tub part of the arm of a 

 iyphon; but, as warm water was conftantly wanted in an 

 elevated part of the premifes, and as all the water ufed was 

 railed by a lifting pump from an adjacent well, an opportunity- 

 appeared to prefent itfelf, both of economizing labour, and of 

 making ufe of the warm water of the upper furface of the 

 worm tub. To effed thefe objeds, I made the pipe coming 

 from the well immediately communicate with the tub, and an- 

 nexed the pump, by means of another pipe, to the upper fur- 

 face of the tub. By this conftruftion, there was every reafon 

 to conclude that it would be practicable to pump off the warm 

 water, and alfo^ that whenever the pump was worked to fupply 

 the other demands of the laboratory, the water in the worm 

 tub would be conftantly changed without additional labour. 

 It was further thought necefTary to add a valve of fafety to the 

 upper part of the tub, and two flop cocks, one on the pipe 

 leading from the well to the tub, and the other on the pipe 

 leading from the pump to the tub, in order that by the regula- 

 tion of thefe cocks, water might be had either immediately 

 from the well, for other purpofes of condenfation, 8zc. or it 

 might be drawn from the worm tub for procefTes requiring 

 warm water, or for ufes to which warm or cold water might 

 be indifferently applied. 



To give a better idea of the apparatus, I have fubjoined 

 the following outline, Plate XII, where A reprefents the worm 

 tub; B a pipe leading from the well; C a pipe communicating 

 immediately from the pump ; D a valve of fafety, E a pump ; 

 F a well; and G G flop cocks. 



The apparatus when made upon a fmall fcale, with a The apparatus 

 Woulfe's bottle and glafs tubes, anfwered perfe6tly and pro- ^"""'^^'^ P"^- 



•r , . , .. -/- . T -r, T .. , , feftlyinthe 



niiled to be a valuable acquilition. 1 with 1 could relate thcfmaii way; but 

 fuccefs of the fame experiment made upon a large one: But, failed on a large 

 notwithftanding the beft workmen in London were employed, 

 they could not make the joints of the worm tub fufficiently 

 tight to refill the preffure of theatmofphere for more than a few 

 fucceffive hours. 



I fliould not. Sir, have offered to you the refult of an un- 

 fuccefsful experiment were it not from an apprehenfion that 

 the worm tub recommended by Sir Alexander Edelcrantz might 

 be no.lcfs difficult to conftru^ than the one I have defcribed. 



Allow 



