M-Jions and KibUudcs of Can-.^hor at th S,urfr.c: of m.Ur. -^o^ 



In narrow vefl-cls, the feaion of ilie column would not be completed in a decade (ten 

 dnys), even though the water might be extremely pure. 2. When the column of camphor 

 has proje£img parts, the liquid may be fecn ifTuing by preference from certain points of the 

 co.umn, covermg the furfacc of the water, and driving fmall floating bodies before it, in the 

 fame manner as floating bodies go and return in a bafon into which the water of a canal 

 enters with rapidity. 3. If a fmall piece of camphor, already wetted at one end, be brou-^ht 

 near the edge of water co.itained in a broad faucer, and be made to touch the faucer itfelf. 

 .t dcponts a vfible hquor, which is oily, and by attaching itfelf to the faucer dertrovs the 

 adhefion between the venel and the border of the water ; fo that the water retires on account- 

 of the affinity of aggregation, which not being oppofed by the attradion of the faucer, 

 eaufes the water to terminate in a round edge. If you remove the piece of camphor, the 

 water wdl not return to its place until the oily fluid is evaporated. 4. In the fame manner 

 when the column of camphor is half immerfed in the water, the oily liquor which ifl-ues forth 

 dettroys the adhefion of the water td the column, and produces a fmall furrounding cavity 

 The fo lufon Hops, or is retarded for a moment, until the fluid, extending itfelf ;ver the 

 water, becomes evaporated : the water then returns to its place, and touches the fame part 

 of the camphor; the folution begins again, and in this .nanner the procefs is eifeftcd by al- 

 ternations of contaa and apparent repulfion. 



The rotation of fmall pieces of camphor at the furface of the water, is fimply the mc 

 chamcal effed of the re-aftion which the oily liquor, extending itfelf upon the water exer 

 afes aga.nft the camphor itfelf. If the retro-adive centre of percuffion of all the iets' do 

 not comc.de with the centre of gravity, a combined motion of rotation and progrcffion 

 muft follow. Since the departure of the oily folution takes place only at tlie furface of 

 the water, the rotation cannot be efTeded but round an a.xis perpendicular to the horizon- 

 and fince in fimilar bodies of different magnitudes the algebraic ratio of the (ides to the mafi 

 .ncreafes in the inverfe duplicate ratio of the fider themfelves •, the fmall particles mud have 

 proportionally more jets, and mu(t revolve more fpeedily than the larger. 



The Author redi.ccs to one general rule all the apparent irregularities' cbfervable in the 

 motions of the camphor. When thefe fmall parts are briflcly moved at the furface of the 

 water, .f you touch this fluid with any other body, whether conduftor or non-cnnduftor of 

 eleancny IS of no confequence, provided it be well cleaned from every oily fubllance- in 

 this cafe, the motion of the camphor will not be affeftcd. But if the fame body be afier 

 wards greafed by a fmall drop of fixed oil, or a greater quantity of volatile oil, and then 

 applied to the water at one extremity of the plate, you will dlfcern a fcarccly perceptible film 

 advancing at that Inftant over the whole furface of the water, which will reoel the fmall 

 morfels of camphor, and, as If by a rtroke of magic, deprives them of their motion and vi- 

 vacity. One ounce of oil. poured on one extremity of a bafon of water of twenty feet 

 diameter, very foon ftops the motion of camphor revolving at the other end. This rapid 

 d.ffufion even of a fixed oil over u great furface of water, prevents the camphor from 

 extending itfelf, and (tops the folution and rotation of the fmall p irtlcles.It Is for this reafon 

 Lkcwife. that particles of faw-duft, foakcd In fixed oil, begin to turn the moment they touch " 



' So in ihc oriKln,!. In truih. ,!,c f.Jc, of like folijs arc in ,hc invcrfc triplicate r.tio of ,|,ar folMi.ic, 

 Th.« ovcrnglit of ,l.c .ngeiuou, Auihor docs not impair hU dcduflion wij, rcgar^l ,0 th. velocities of rotation, n". 



the . 



