390 Mr. Nicholfons Defer ipt ion of a new Injirument 



Mr. Quin. The firft is certainly the moft per- 

 feft inftrument we poffefs, its weights being 

 adjufted to the different fpecific gravities of 

 fpirits, by experiments made at numerous varie- 

 ties of ftrength and temperature. The" latter 

 having no additional weights, but depending 

 entirely on the graduations of its ftem, is much 

 more ready in pradlice. All ' s originality con- 

 fifts in its ftem being the fruftum of a cone, 

 whofe larger end h uppermoft, by which happy- 

 contrivance the ftem is fliortened, and its gra- 

 duations are all kept nearly equal. 



I ftiall now proceed to defcribe the inftrument 

 I have caufed to be made for the general pur- 

 pofes of finding the fpecific gravities of bodies. 

 Its dimenfions are likewife added. * 



A A reprefents a fmall fcale. It may be taken 

 off at D Diameter is inch. Weight 44 grains. 



B a ftem of hardened fteel wire. Diameter 

 Teo inch, 



E a hollow copper globe. Diameter 2tV 

 inches. Weight with ftem 369 grains. 



FF a ftirrup of wire fcrewed to the globe 

 atC. 



G a fmall fcale ferving likewife as a counter- 

 poife. Diameter i\ inch. Weight with ftirrup 

 1634 grains. 



* See the figure to which thefe letters r?fer in plate IL 

 vol. II. 



The 



