Chap, 2.3 to the Height of the Column. 41 1 



the veffel is evidently much larger than the firft j be- 



caufe the bottom F G fupports only the column 



I F G K, equal to that of the veflel (fig. 4.) and 



this column exercifes its preflure independently of the 



refidue of the " ater in the veflel, which is fupported 



by the fides E F, H G, of the veflel (fig. 5.) But 



the principal difficulty confifts in comprehending how 



the bottom of the veflel N O is dill prefled by a 



weight of fix pounds, although one pound of water 



would be fufficient to fill the veflel. It is accounted 



for in this manner : it is ceruiin that upon the portion 



T V of the bottom N O, there is a preflure equal 



to that of a column of water of which T V is the 



bafe, aid L T the height. If, upon every ether 



fimilar portion of the fame bottom, there is a preflure 



equal to that of the column L T V Q^, the bottom is 



equally prefled upon all its parts. For inftance, there 



is a preflure upon the portion V X equal to that of 



a column of water QV X R, which is itfelf equal 



to the column LTV Qj for the fmall column of 



"water P V X S, which refls above, has a pro- 



penfity to be elevated by the preflure of the adjacent 



column LT VC^and with a force equal to the excefs 



L M P Qj)f this great column over the fmall one ; 



therefore the upper part, P S, is prefled by the fame 



power -, but the re-action is equal to the preflure. 



The part P S re-acts with a force equal to. the excefs 



L M P Q^of the great column over the fmall one. 



There is, therefore, a preflure upon the portion V X 



of the bottom N O, from the fmall column of water 



PVXS, and from the re-action of the part PS, 



equal to the prefiure of a column of water, QJP S R, 



both of which added together are equal to the pref- 



fure of the column LTV Q^ What has been faicl 



of the portion V X may be faid of all the reft. Hence 



it 



