411 lly draft at ic Paradox. [Book VII. 



it follows that the bottom of the veffel (fig. 6.) is 

 every where equally preffed. 



There is a maxim deduced from what has been 

 ftated, which is termed by philofcphers the hydroftatic 

 paradox ; it is neverthelefs founded upon the fureft 

 bans of truth, and has a confiderable influence in al- 

 mpft all hydraulic engines, viz. " that a given quantity 

 of water may exert a force two or three hundred times 

 kfs or greater, according to the manner in which it 

 is employed." If, for inftarice, the fame quantity of 

 water as the veffel (fig. 5.) will contain, is poured 

 into a veffel refembling that of (fig. 6.) but high 

 ' enough to contain it, the preffure upon the bottom 

 N O will be confiderably greater than that upon the 

 bottom F G. 



One of the molt ufeful machines to mew that a 

 fmall quantity of water is capable of great preflure, 

 is the hydroftatic bellows. This machine (Plate VI. 

 fig. i.) confifts of two thick oval boards, each about 

 three feet broad, and four feet long, united to each 

 other by leather, like a pair of common bellows, or 

 a barber's puff. Into 'the lower board a pipe B, 

 ieveral feet high is fixed at e. Now, in mewing ex- 

 periments with this fimple machine, which even the 

 reader himfelf might eafily make, let water be poured 

 into the pipe at its top C, which will run into, the 

 bellows, and feparate the boards a little : then to mew 

 how much a little water will be able to effect by pref- 

 fure, let three weights, each of an hundred pounds, be 

 laid upon the upper board. Now if we pour more 

 water into the pipe, it will as before run into the bel- 

 lows, and raife up the board with all the weights upon 

 it. And though the water in the tube mould weigh 

 in ajl but a fmgle pound, yet the prcfllire of this fmall 



force 



