pears at first sight unexceptionable, is in fact inconsistent 

 with the general principles of the theory. 



It appears therefore on one hand, that the considenilion Repulsive force 

 of a repulsive force is indispensably necessary to the perfect ^'^^^^^y^oThe 

 solution of the problem ; and on the other, tluit such a force solution; but 

 as there is reason to infer from experiment is not capable of ^^JJ.^^j^'^J^^^ 

 producing effects similar to those of the capillary affections experiment 

 of liquids. There appears to be only one way of avoiding "^"^jf^'^X'^j^ 

 these difficulties, which is, to suppose that a part of (he 



force of repulsion only is concerned in that actioii which is PaVt of this 

 J ^ I •' . iorce only sup- 



observed at sensible distances, whde another part is so con- ^^^.^^ ^^-.^g. ut 

 fined to the particles in immediate contact with each other, smsible dis- 

 th;it if we suppose a liquid to be divided by any imaginary ''"^'^^' 

 plane surface, the particles on one side of this surface can 

 only act on the particles on the other side in a direction per- 

 pendicular to it, leaving them completely at liberty to move 

 without resistance in the direction of the surface itself. This 

 hypothesis has been tacitly assumed by Mr. Laplace, with 

 respect to the whole force of repulsion ; but in any shape it 

 is still an hypothesis only, and the reasoning founded on it 

 can only be considered as demonstrative, so far as its results 

 are justitied by a coincidence with facts and experiments. 



Suppose a column or stratum A B (Fig. 5) terminating Supposition of 

 in a curved surface C D, to be contained between two pa- ^,[^^.jj™ j* a 

 rallel planes perpendicular to the tangent E F ; then the roncatc sur- 

 action of the pai tides below E F^ will have no power to ^^^' 

 move the column in a vertical direction ; but the portion of 

 the substance included between the curve and its tangent 

 will tend to elevate it, and the more in proportion as the 

 curvature is greater; the number of particles within a very 

 minute distance from the column being directly as the cur- 

 vature, or, where the surface has a double curvature, as the Surface of dou- 

 sum of the two curvatures in directions perpendicular to ^^^*^"*"''^^"'^* 

 each other. And if the line G 11 be every where as much 

 below E F as C D is above it, the action of the particles, 

 cut off by this line on the column A B, will be equal to that 

 of the particles above E F, and will produce an equal force 

 tending to raise it ; hence, if all these particles be removed, 

 the remaining parts of the substance below G H will attract 

 the column with the same force as was before counteracted 



by 



