given in the Encyclopoedia Britannica. 283 



equal to ^ K + ^ K sin tf, and the attractions upon each of 

 the remaining sides is only equal to | K ; wherefore there is 

 an excess of attraction equal to | K sin 6, which causes the 

 drop of liquid at the upper end of the canal to press on the 

 fluid above it, with a force equal to ^ K sin 6 acting upward, 

 and sustaining the part of the ring cut off by the vertical plane 

 LP." 



Now, here it is to be remarked, that the force ^ K + ^ K sin d, 

 is part of the entire force K, and that it acts not upwards, but 

 in the direction of the normal to the curve surface at L, and 

 that, instead of tending to support the superior fluid, it merely 

 goes to generate a compression in the interior nucleus. 



If we examine the composition of this force aright, one part 

 of it, K cos 6, is acting in the direction of gravity, and the 

 other, K sin 6, impels the drop of fluid at L in a horizontal 

 direction ; but in establishing, from this decomposition, the 

 conditions of equilibrium, we are at liberty to reject none of 

 these forces ; yet, granting that we were so, it appears to me 

 very improbable, that the part ^ K sin tf retained, would pro- 

 duce the effect in question. I can easily conceive that a repell- 

 ing force at L, might tend to support the superior fluid ; but 

 how an attraction can do that is to me quite mysterious; it ap- 

 pears as if I were told, that, standing to the northward of an- 

 other person, and pulling him, this exertion would tend to push 

 me northward. 



My principal object, in making these remarks, is to prevent 

 the belief that a complete solution of the difficulties of this im- 

 portant subject has been attained. I have as yet seen no satis- 

 factory explanation of the elevation and depression of the siu-- 

 faces of fluids, when brought in contact with solid matter ; and 

 these investigations induce me to believe, that the whole ap- 

 pearances are due to a change in the corpuscular arrangement 

 produced by the simple contact of a heterogeneous substance, 

 the laws and nature of which change are, and perhaps for ever 

 will be, unknown to us. 



32. St Andrew's Square, 

 Edinburgh, Feb. 8. 1830, 



