sg6 Engine for rating Water by the lateral. 



The lateral motion of a current of air will, to a certain extent, produce the fame effeft 

 as a current of water, but to what height water may be raifed in this way, I have hitherto 

 made no experiment to determine. The power of an inftrument in the form of Mr. 

 Bofwell's ventilator * is very confiderable when made upon a fmall fcale, if the fmall tube 

 be forcibly blown through while the end of the vertical tube is placed in water, one ex- 

 piration will caufe the water to rife in it feveral inches. 



I am, SIR) 



Your's, &c. 



WILLIAM CLOSE. 



LETTER IL 

 SIR, 



HAVING conftrufted the model of an engine upon the preceding principles, on the 

 29th of Auguft laft, I fet it to work, and kept it in a£tion for feveral hours. 



The rarefying tube E, fig. i. was placed within the afcending water tube C, until they 

 had both entered the fpherical veflel ; they were then divided, and the end of the water 

 tube was ufed as the fupport of a metallic valve, which, by its weight, clofed the opening 

 of the tube E. To one fide of this laft tube was fixed another fmall one, which opened 

 into the external air by the fide of the pipe to let out water, and both thefe were clofed 

 by the end of the lever L, or lower valve. This fmall tube, at the fame time that it ferved 

 for admiflion of air, to haften the defcent of water, ferved alfo to contain the wire which 

 raifed the upper valve, «, fig. a. 



The lower valve was covered with leather, and when it was well moiftened, and the 

 engine had been in aftion for fome time, I could perceive no fault. 



The method of making the engine work itfelf, which I adopted in imitation of the plan 

 propofed by Mr. Bofwellf, anfwered very well: the lower valve was opened between 

 fix and and feven times in a minute, and water always flowed out ; the higher valve com- 

 pletely prevented the diminution of the ftream through the conical tube, and when it was 

 lifted by the clofing of the lower valve, no difference could be perceived, although a little 

 air was admitted at each life. 



The defcending branch of the fyphon in the higher vefl"el H, was made of confiderable 

 length, to prevent a conftant dribble, and to make the reciprocation end at once. The 

 fyphon of the lower or defcending velfel was made full as wide as the other, in order that 

 the weight might preponderate quickly, and clofe the lower valve immediately after 

 raifing the higher. The upper veflel was hung upon the fide of the refervoir, and fupplied 

 with water over the edge by a fyphon, one aperture of which was made of a proper width. 

 The capacity of the lower veflel was about five ounces; the higher about feven; but 



• Philof. Journal, IV. 4. t Philof. Journal, IV. 117. 



was 



