47* 



Proceedings of Learned Societies. 



[Dec. J, 



*vith the pifton-rofi attached to one end 

 ot' the iaine lever or levers ; and as the 

 ileam is let on tlio pilton from the iream- 

 boilcr, it will lift or compicts the lever 

 or levers as may be required. The lever 

 Or levers may he fixed lo as to woik per- 

 pendicularly, horizontally, or in any 

 other requiied direction. The fliape, 

 (ize, or f-^rni of the prcfs may he varied, 

 a-'reeuhly to exifting circuraliances. The 

 Lnives may be made fall to tlic plfton- 

 sod, or any con\'enicnt thing connected 

 \\\ih the pifton-rod ; or othervvife the 

 pillon-rod may t)C made fait to the lever 

 or levers, or knife or knives, or other 

 lev-ers made be ufed if found neceflary 

 fo as to work the knives; but thjfe ki>ves 

 may be fixed in various other ways, fo 



as to chip fiiflick, logwood, and other 

 ^voods ; and may alfo be lixcd to any- 

 proper thing uhich will >\orl; to and 

 agam by the piilon-rod being attached 

 to fonie part thereof. The ihears may 

 be woiked by the pilton-iod being at^ 

 tached to the end of the ihcars-lcver ; 

 or there may he a fccond lever, or more 

 if required, lb that the pilton-rod may 

 be attached to fome convenient par^ 

 thereof, in order to give motion to the 

 Ihcars. l\Ir. DevereLl applies the lam<» 

 mode for the working or giving motiur» 

 to bellows. In that cafe the pifton-rod 

 may be attached or made fall to the 

 back p-.u-t of the bellows, or feparate 

 levers may be made life of, which may 

 be made fad to any part of the bellows. 



PROCEEDINGS OF LEARNED SOCIETIES. 



TS^ATIONAL INSTITUTE o/TRANCE. 



COUNT RUMrORD, has lately laid 

 before .ti)i» learned Society, an ac- 

 count of fome curious and iiiteicftiug cx- 

 perlmciUs with obfervations on the ad- 

 lielion of the particles of water to each 

 other. He fets out with obfervLng " that 

 >fte often fee frnall bodies of u fpecific 

 gravity, nnjch exceeding tl'.at of water, 

 II ,.it "upon the fiirfacc of that tluid. 

 Such fur example, are very fmall grains 

 of land, fine liliugs of the metals, and 

 *vcu hnall fewhig needles. So extraor- 

 daiary a phenomenon has not failed to 

 excite tba attention of [jlnlofophers, and 

 ns this is intimately cnnnerted with a 

 fubject of refcarch upon which I have 

 been long employed, 1 fliall here give an 

 account of fome experiments I have made 

 to elucidate the fame, ar.d which iiave af- 

 forded refults of coniiderable intcreft. 

 Sufpct'ting that the prcl'eiice of air iid- 

 licring to thcfc fmall lloatiug bodies, 

 v.hich is generally coufidcrcd as the 

 canfc of their fufpeniion, js not indef- 

 peidubly necclfary for thfc iuccefs of 

 tl'ie es,i:criment, I made the following: 

 exj)erinient : — Having hah" tilled with 

 xvater, a wine glafs one inch and a half 

 diamctt!r at its; edge, I poured on the fur- 

 face of the water a ftratum of fulphuric 

 ether, on? inch and a half in thicknci's ; 

 and when the whole was perfectly fiill, I 

 took a very fmall fewing needle with a 

 panv.f pincers, which 1 introduced below 

 the other, where holding it liorizontally 

 at u fmall didance from the furtace of 

 tUe M iiLcr, I let it fail. The pccdle dc- 



fcended to the water and there floated on 

 its i'urface. I made the next experi- 

 ment with granulated tin, which defcend- 

 ed through the etl-.er, and when it arrived 

 at the l\nfacc of the water it remained 

 lloating. 1 then reduced a tlrop of 

 mercui-y into fplicrules of about onc-fi.\- 

 tieth (jf an inch in diameter which I 

 carefully conveyed into the ilratam of 

 ether, through which it defccnded to the 

 fnrtace of the water and there remained 

 floating. 



" \\ hen the eye vvas placed lower thait 

 the furfac(.- of the water, and the fpherulc 

 wasohfcrved by looking upwards througfi 

 the glafs, it appeared I'ufpcndcd in a kind 

 of bag, a little below the level of the fur- 

 face. Having placed a fccond fpherule 

 of mercury on the furfacc of the water, it 

 innncdiately moved towards the former, 

 and approaching it with an acceleratctj 

 motion, fell down into the fame cavity, 

 which tlien be<-amc longer ; but the two 

 fphcrules did not unite. Having placed 

 a third fpherule on the furface of the wa- 

 ter, it joiiicd the two others, but the 

 weight of thclc three fpherules together 

 being too great to be iupportcd by tl'.e 

 kind of p.elHcle which is formed at the 

 Airt'ace of the water, the bag was broken, 

 and the fphcrules (icfceuded through the 

 w ater to i.lie bottom of tiie vcflel. When 

 the experiment was made u,ith a fpherule 

 cfnicrcm-y, a little larger, namely about 

 the fortieth or tlftietli of an inch, it never 

 failed to break tl;e pellicle of the water, 

 and to dcfcend through ti'^n.t liquid to the 

 bottom of the glaii. But wlien the vifci- 

 dity of the water w;4S iucrtafcd by dif- 

 iulviiig 



