Defcriptlen of a Support applicable to Salances, joj 



The piece N O is perforate*!, and may be Aided up and down the ftem A B, and alfo 

 moved horizontally to the right and left. When it has the proper height, it is fixed, by 

 means of the prelTing fcrew V, that is to fay, ill. when its height is fuch that the ftop m' 

 rcfts on the edge of the notch yy, or when N O, being at its loweft limit, the diflies of 

 the balance are in conta£l with the table or horizontal plane, fo that it may be raifed after- 

 wards through the whole height/«; and, 2dly, that the firing F F (hall be in the fame 

 vertical plane with H G. 



The notch in N muft be fo placed that the axis of the prifmatic part of the tail of the 

 fork and the ftring F F" fhall be always in the fame vertical line parallel to the axis of th» 

 ftem A B. 



Thefe arrangements being underftood, let us imagine the two branches n q oi the fork to 

 be drilled through with holes of different fizes, to receive the horizontal pins g g of diifereat 

 diameters, and we (hall poflefs an apparatus quite adequate to weighing in the air with 

 balances which have their beams fupported between the ufual frame and rings. 



Whatever, in fad, may be the fize of the balance intended to be ufed, the extremity 

 Qf its clip, or frame, is to be introduced between the fork n q, and a pin of fuch a fize a» 

 to enter very freely into the hole at the top of the clip muft be pafled through ; after which 

 the piece O N is to be placed, fo that the conditions before mentioned with regard to this 

 piece ftiajl be obtained ; and in this pofition it is to be fixed with the thumb-fcrew V. This, 

 operation being made, the difhes of the balance are to be loaded, which, being In conta£b 

 with the table or horizontal plane, cannot move. The fmall ball k being then taken in the 

 hand, the ftring muft be drawn fo that the balance fliall rife very ilowly. If the fcales be 

 not in equilibrium, the beam muft be fuffered to dcfcend, and the procefs of weighing ba- 

 completed by altering the load as ufual. 



A counterpoife Q, fufpended on the ftring F G, forms an equilibrium to the weight of 

 the balance. By means of this precaution, the refult of all the efforts which fupport the- 

 puUey P paffes in all cafes through the axis of the rod A B-, which, confequently, will 

 have no difpofition to bend or incline. 



But if it be propofed to ufe an hydroftatical balance, a fmall table O' N, Fig. 3, is to 

 be adapted to the rod A B, which, by means of a cylindrical perforation in O', can Aide 

 up and down the rod, and be fixed at any required height by the thumb-fcrew V. An- 

 other piece, or little table, K' K, is placed upon V N, fo that the holes T correfpond to 

 the centre of the dlflies, below which are placed the hooks intended to hold the body fuf- 

 pended in water, and K' K' is fixed upon V N by means of the fcrew V. 



This adjuftment being prepared, the piece N O is to be placed on the table K' K', fo " 

 that, ift. the whole height of the balance ftiall be comprehended between this piece and 

 the fmall table, and the diflies fltall be conta£l with the fame, their centers correfpohding 

 with the openings made in T; 2d. that K K' fliall be fufficiently raifed to admit of the 

 veflels W W of water being placed beneath, fo as conveniently to immerfe the, body in- 

 tended to be weighed in one of thefe vefTels. 



Vol. V. — November 1801. Rr Thefe 



