The First Steam-Boat

C 16 ) your Finger, immerfe the other in Water«, when -the Tubeis full of Ær, the Water will rife but io a (mail Height : If yoa take away your Finger that the _Air that is comprefied may go Out, the imaginary Sunace that you conceive in the Water juft at the Bottom of the Tube is lei's pieffed; juft again# the hole of the Tube, 1b that the Water will riie up in the Tube till it comes up to the fame Height with the external Water. FChe Preffure upon -theLower?arts 'which anfcsfroin the Gravity oftheSuper-incum beat Liquid, exerts it Je If every way, and. every way equally. In Tubes that have a. Communication, whether Equal or Unequal, whether Strait, or Oblique, a Fluid rifes to the fame height, that is, all the Parts of the Uy yer Surface are in the fame Horizontal f lace. The modern PhilofoyherscwtceMeSlxiidS to corm fl of Particles fmall., fmoothj hard, and fpJierical-., according to which Opinion every PaiHcle is of it feix' folid or a fixt Body, and, when conûder’d Tingly, is no Fluid, but "becomes io, only by “being join’d with Particles of the fame kind. The more perfef? a Fluid is, the more fafily it will yield to all ImpreffionS? and the more eafily yzilltheparts Coalefce be- ing