PRESSURE UPON THE BASE OF VESSELS. 177 



plate will be pressed down before the whole quantity 



jf 40 gr is poured into it; this proves at once that 



u a vessel which becomes gradually narrower from the 



Bottom towards the top, the pressure upon the base is 



greater than the weight of the contained liquid. This 



/essel, however, cannot be strictly compared with vessels 



[ and 2, because it has a wider base. Vessel 4 is 



herefore finally used for the same experiment. It has 



jot a sufficient capacity for holding 40 gr of water ; but 



is the water will begin to escape from this vessel when 



t is filled up to the same height as that at which the 



v r ater escaped from vessel 1, it proves that, in a vessel 



tarrower at the top than at the base, the pressure 



pon the base is the same as that upon the base of a 



essel with perpendicular sides, if the area of the base 



nd the height of the liquid is the same in both 



essels. 



The upper part of vessel 2 is too wide, and the lower too short, for 

 sing clamped in the retort-stand. Therefore, in order to support 

 , cut a thin strip of zinc, 2 cm wide and about five times as long as 



B 



an.proj.). 



liameter of the wide part of the vessel ; bend it into the form 



>wii at A, fig. 127, solder the two straight parts together to make 

 ;nulle which can be clamped in the fork of the retort-stand, and 



* >pend the vessel in the ring in the manner shown at B. 



N 



