ON CAPILLARY ACTION. 291 



of glass, in the Memoirs of the Petersburg Academy, vol. 

 XII. These confirm the law, according to which the 

 heights are reciprocals to the homologous lines of similar 

 bases. Mr. Gellert farther concludes from his experiments, 

 that the elevations of a fluid are the same in rectangular and 

 triangular prisms, the bases of which are equal. But he 

 admits, that this is not so certain as the law of the heights 

 being reciprocal to the homologous lines of similar bases. 

 In fact it has just been seen, that there is a difference of an 

 •ighth between the elevations of the fluid in two prisms, 

 the bases of which are equal, and one of which is a square, 

 the other an equilateral triangle. The experiments related 

 by Mr. Gellert do not afford sufficient data, to compare 

 their results exactly with the preceding theory. 



If the base of the parallelopipedon be a rectangle, the A narrow paral- 

 larger side of which is equal to «, and the other side, sup- lelo S ram - 

 posed very small, equal to /, we shall have bz=al, andc=: 



2«+2 I: consequently h =lM^l5. =? x f 1+1}; 



2 ul \ a J 



and by neglecting — we shall have h—q^ agreeable to ex- 

 perience. 



" If the indefinite vessel, in which the parallelopipedon Wheresereral 

 is immersed, include any number of fluids placed horizon- cerlied ' 

 tally one above another ; the excess of the weights of these 

 fluids contained in the tube, over the weight of the fluids 

 which it would have contained without capillary action, is 

 the same as the weight of the fluid that would rise above the 

 level, if the vessel contained only that fluid in which the in- 

 ferior extremity of the parallelopipedon is immersed." 



In fact, the action of the prisms and ,this fluid on the 

 same fluid included in the tube, is evidently trie same as in 

 the latter case. The other fluids contained in the prism 

 being raised sensibly above its base, the prism has no action 

 on either of them to raise or depress it. As to the recipro- 

 cal action of these fluids on one another, it would evidently 

 be destroyed, if they formed a solid mass together, and this 

 we may suppose without any disturbance of equilibrium. 



(( If the vessel contain but two fluids, in which the Case of tw» 

 prism is entirely immersed, so that its superior part is in 



one 



