PHYSICAL AND LITERARY. ag 



fefleding the light copioully in different 

 diredions, alTumes the reiplendent white 

 colopr of unpohdied iilver. 



19. After it is thus proved by an opti- 

 cal argument that the drop is really not in 

 contadl with the plant which fupports it, we 

 eafiiy conceive whence its wonderful volu- 

 bility 



projefl on the bottom of the veiTe!, according as they are 

 fonvex or concave. 



Some writers have been fo inattentive as to afcribe the 

 inotions in the firft cafe to an immediate attraftion between 

 the fwimming body and the fide of the vefTel. See Ueljham'i 

 l,eiiures. Before I had obferved the fourth and fixth cafes, 

 I thought the fhxnometia might be all explained from this . 

 principle, that thelight bodies always tend to the highell 

 parts of the water. It has been fuggefted to me by fome, 

 that this tendency, combined with the greater Or lefler im-.. 

 merfion of the bodies, upon account of the ring of .water 

 yvhich they elevate or deprefs, may produce all the different 

 cafes; and by others, that the whole is explicable from the 

 fmgle principle of attraftion between the parts of water" 

 )vhich caufes two drops to run into one. I believe it will 

 be found, on due confideration, that none of thefe account?^ 

 is fatisfadory : but there is no reafon to defpair of coming 

 to the bottom of thefe ^J/^a-ww^wij ; lincc other motions of 4 

 like kind have been fuccefsfully explained. Thus the run- 

 ning of a drop of oil towar'^s the concourfe of two glafs'?-' 

 planes and the motion of a bubble on the furface of liquors, 

 ivhen the glafs is held obhquely towards that point, where 

 the glafs is inclined to the liquor in the fmalleft angle, are • 

 eafily underftood from the diredtion of the compound force 

 v/ith which the drop and bubble are adted. 



