IMPROVEMENTS IN HYDRAULIC ENGINES. 3 



valve opening outvWs at the air vent of A will be fufficieht. 

 The pipe at K is t< conduct water from the bucket F to that 

 of the cock D. T.ere are two ranges of refervoirs reprefent- 

 ed, to fhew the mithod of raifing water by this engine about 

 thirty feet high : aore would be ufelefs, and even a fecond 

 would in very fewinftances be found neceffary, except when 

 the fall of water fr«m R to D was very fhort, in which cafe it 

 would be better ttiufe fome other engine for railing water to 

 the required heigh. 



In comparing tbfe two engines, it will be found that their Comparlfon of 

 powers and capacities are nearly fimilar. the powers of 



1 . In both the greater the height of the original fall of wa- g ; ne s 5 numeri- 

 ter, denoted by tlfe pipe R D, and the greater the quantity eall y ftated « 



of water which if can fupply in a given time, the greater 

 quantity can be riifed by thefe engines in a given time. 



2. Both engires can be conftru&ed fo as to raife water 

 above the origiml level, and from below to the furface, or 

 from a pit. I 



3. By a fuccdfive number of refervoirs both engines can 

 be brought to rife water to any height ; but as they will raife 

 a fmaller quaniity as the height is increafed, the quantity 

 wanted in a givsn time, and the expence of conflruclion, will 

 limit the extent of their elevation. 



4. In both engines the diftance from one refervoir to an- 

 other, muft alvays be lefs than that of the original fall RD. 

 The circumftanres in which thofe engines differ arife from, 

 the difference of their manner of action. 



5. The Schennitz engine operates by caufing a fall of wa- 

 ter to comprefs ail, which re-a6ting on other water forces it to 

 rife in a pipe to a certain height. Mr. Goodwyn's engine a<5ts 

 by caufing a fall of water to rarify a certain quantity of air, 

 into whofe fpace the preffure of the atmofphere forces, when 

 permitted, a quantity of water. 



6. Hence in the Schemnitz engine, the preffure acting from 

 within outivards, tends to burfi the veffels ufed in the ftructure, 

 and to open and extend any fifTures which may chance to be in 

 them. 



7. In Mr. Goodwyn's engine the preffure acting from with- 

 out inwards, clofes all the parts of which it is compofed more 

 together, tends to make its pipes and veffels more ftaunch, 

 and in any fiflure makes its fides operate like valves to fhut it 

 up. 



B 2 3* The 



