OOQ. DESCRIPTION OP AN fTYDRAULIC BELLOWS. 



its nozzle compared with this, is as ,73 to ,60 in diameter, 

 but it does not produce fo great an effed in bringing on the 

 beat, and the voice of this is fo great as almoft to drown that 

 of the common one. The only difference in other refpe&s is, 

 that in the hydraulic bellows the pipe goes underground for 

 about eight {eet, and the conducting pipe of the other comes 

 down about the fame diftance from the (hop above. 



If any further particulars are neceflary for your comment on 

 this fubjecl, they are at your fervice, 

 I am, SIR, 



Your very obedient Servant, 



J. C. HORNBLOWER* 

 EajlRoxi'f City Road, Feb. 12, 1802. 



DESCRIPTION. Plate XII. 

 Defcription of A t The plunger, or working part of the bellows, 1 8 inches 

 its ftrufture and fq Ua re within, which receives the air by a valve in the hinder 

 part opening inwards, which at the ftroke by the rockflaff E, 

 throws it down the tube indicated by the dotted lines, which 

 has a valve opening into the refcrvoir D, whence it is led to 

 the tuyere by the pipe P. Length of the plunger 20 inches, 

 ftroke nine inches. Diameter of P three inches ; of the noz- 

 zle 0,6 inches. 



The whole is placed in a pit or ciftern, having- water fuf- 

 iicient to rife to the lower end of the tube where the valve 

 hangs ; this tube is the only communication between the up- 

 per part and the refervoir D : when as much water is poured 

 in round the working- part over the wafh boards, as will rife 

 within five inches of the upper edge of them, the belloWs is 

 ready for ufe. The little frame work ferves to keep it from 

 o fifing, and affords a convenient fupport for the balance and 



the rock ftafT. 



I mould obferve, that the area of the pit or ciftern ought 

 to be at Ieaft twice as much as that of the plunger A *.' 



* From the preffure of other bufinefs, it has not been in m>" 

 power to vifit this manufactory, in order to afcertain the caufe of 

 the difference here ftated j but I fhall give the facts more particur 

 Jarly in the next number. W. N. 



XIII. On 



