of Natural Philosophy, 155 



same sense. But if in the phrase " divisibility of matter" 

 be included the additional idea of discerptibility, or the pos- 

 sibility of being separated into parts not in contact, then the 

 property is one which belongs in no degree to pure exten- 

 sion. In neither case does the distinction made in the pro- 

 position as quoted above appear to have any foundation. 

 That matter is infinitely divisible in the first sense, is almost 

 self-evident: whether it is so in the last, (admitting the ex- 

 ercise of any supposable power which does not change the 

 nature of matter,) is a question which lies beyond the reach 

 of the human faculties. 



We notice, in the second place, that three experiments, 

 on the approach of light bodies floating on water to each 

 other, or to the side of the vessel, have been transferred 

 from prop. 5, where they were originally placed to illus- 

 trate the cohesion between solids and fluids, to prop. 4, 

 where, if they illustrate any thing, it must be the cohesive 

 attraction between two solid bodies. It is true that these 

 phenomena are only indirect consequences of the attraction 

 between solids and fluids ; and a schoHum was very proper- 

 ly added by the author, (which has been omitted in all the 

 subsequent editions,) to aid the student in tracing their con- 

 nexion with the proposition. But it is most certain that 

 they have nothing to do with the cohesive force of two 

 solid bodies. When there is an elevation or depression of 

 the fluid around both of two floating bodies, they will ap- 

 proach : when there is an elevation around one and a de- 

 pression around the other, they will recede. These are 

 mere results of capillary action; and as such, admit of an 

 easy explanation from the general theory of Laplace.* — A 

 popular idea of the mechanism of these phenomena will be 

 gained from the following experiment, by v/hich we have 

 been much amused, and which we do not recollect to have 

 seen noticed. Two small globules of mercury, carefully 

 laid upon water, will swim. Let these globules be brought 

 within one or two inches, and it is surprising to observe the 

 rapidity with which they dart together. If one of the glob- 

 ules is forced to the edge of the water, (the vessel being 

 of such materials as to be capable of being moistened,) it 



* See Mec. CAIcste. Sap. v\ dix. Livre : Biot~Trai(e de Physique I. 462. 

 Haiiv I. 237 



