«,l8: Apparatus fir makifig the Hydraulic 



From the Intcreft you fecm to take in the above-mentioned engine, I conclude it will 

 not be unacceptable to you to have a defcription of this method of faving the labour at 

 prefent employed in working it, and therefore take the liberty to fend you a drawing, in 

 which all the veflels are fuppofed to be open at one fide, that the difpofition of the pipes 

 within may be more clearly fcen. 



Simplicity of form, and facility of execution, have been chiefly aimed at in this con- 

 ftruftion ; and I have no doubt but it muft perfeftly anfwer the intention, or I would 

 not trouble you with it. If, however, you fliould be of a different opinion, it will give me 

 pleafure to be fet right by you. 



Description : Plate VI. 



A. The refervoir, or upper level of water. 



B. A chamber made of fufficient ftrength to bear the internal preflure of a column of 



water of the height of A above it, multiplied by its own bafe. 



C. A chamber of the fame ftrength as B, but of a fmaller fize ; it Is placed at the bottom 



of the pit from which the water is to be raifed, and under the level of the water. 

 Thefe chambers would be ftronger with the fame materials, if of a globular or cylin- 

 drical form ; but the fquare (hape is ufed in the drawing, merely for the facility of 

 reprefenting the pofition of the parts. 



D. A pipe, from the refervoir A which pafles through the top of B, and ends near its bot- 



tom, to convey water from A to B. 



E. A pipe from the top of B to the top of C, to convey air from B to C. 



F. A pipe from the bottom of C to the level of the ground at the top of the pit, to carry 



off the water from the pit. 



G. A pipe from the bottom of B to carry off the water from it. 



H. A veffel to contain the water ufed in working the cocks ; it is only placed on the top 



of B to fave the conftruftion of a ftand on purpofe for it. 

 I. A cock, or moveable valve, (worked by the lever there reprefcnted,) in the large 



pipe D. 

 K. A ftop cock in the fmall pipe which conveys water from D to H. Its ufe is to make 



the engine work fafter or flower, by letting water more or lefs quick into H i or to 



ftop it altogether from working when required. 

 L. A moveable valve, or cock in the fmall pipe L K. The lever which works it is con- 



ne£tcd by a ftrong wire with the lever which works I, and is balanced by a weight 



at its oppofite extremity, fufliclent to open both thofe cocks and (hut N, when not 



prevented by a counter weight. 

 N. A cock in the pipe G to open and fliut it as wanted. 

 O. A felf moving valve in the pipe F, which permits the water to pafs upwards, but 



prevents its return. 

 P. A felf-moving valve at the bottom of C, which permits the water to pafs into C, but 



prevents any from pafling out of it ; it is furniftied with a grating to prevent dirt 



getting in. 



R. A 



