O.lO PASSAGE OP IIE/IT THROUGH FLUIDS. 



Appara!n=;for The mifklle of the cavity of this cup is occupied by the bulb 

 Sr""''"^^ "" "^ a small mercurial thermometer of great sensibility. Its 

 tube, which has an ivory scale, is laid down horizontally, 

 and fixed in one side of the cup, through which the tube 

 passes, in such a manner that the lowest part of the bulb is 

 elevated -5-'-^ of an inch above the bottom of the cup. The 

 diameter of the bulb being -\ of an inch, and the hemispheri- 

 cal cup having 1 inch of radius within, it is evident that the 

 upper part of the bulb is yV of an inch below the level of the 

 brim of the clip that contains it. To avoid charging the figure 

 with too many details, the scale of the thermometer is not 

 drawn, but the tube is distinctfy represented. 



The horizontal cross-piece, FG, serves to support a veiy 

 essential part of the apparatus w^hicb remains to be described. 



This cross-piece supports, in the first place, a vertical tube 

 of wood, JM, 6 -f'o inches in length, and 2 inches in diameter 

 without. Its interior diameter is l^Vi"t'li. This tube is 

 supported by a pi-ojecting collar (represented in the figure) 

 21 inches in diameter, which rests on the cross-piece, FG, 

 It is a vertical and central section of this tube that is represent- 

 ed in the figure; and it is dotted, in order to distinguish it 

 frovn the surrounding parts of the apparatus. 



The lower part of this tube is plunged x'V of an inch under 

 the surface of the water in the large cylindrical vessel, K L ; and 

 it is placed precisely above the wooden cnp in the prolongation 

 of its axis, the lower extremity of the tube being at the distance 

 of -j^-^ of an inch above the horizontal level of the brim of the 

 cup. 



On the top of the tube of wood is placed a cylindrical vessel, 

 N O, of sheet brass, 3 inches in diameter, 2^ inches high ; 

 which has a lateral spout, P Q, placed a little above the level 

 of its bottom. 



From llie middle of the bottom of this vessel there descends 

 a cylindiical tube of brass, 6 inches in length, and 1 inch in 

 diameter, which ends below in a hollow conical point, as re- 

 presented in the figure. 



R S is a vertical and central section of a funnel of brass, which 

 ends below in a cylindrical tube of xo- of an inch in diameter, 

 and () -/^ inches long. This funnel is kept in its place, in the 

 axis of the cylindrical vessel, NO, by the exact fitting of its 

 upper edge upon that of the vessel into which it is adjusted. 



The 



