DESCRIPTION OF ATKINS's HYDROMETER. 279- 



O, and in one whofe fpecific gravity was .843, to the lower 

 divifion O ; the intermediate divifions anfwering to interme- 

 diate fpecific quantities. With No. 1, it indicates fpecific 

 gravities from .843 to .880; with No. 2, from .880 to .918 ; 

 with No. 3, from .918 to .958 ; and with No. 4, from .958 to 

 1.000; the furface of water in which the inftrument is made 

 to float with the latter weight, exa&ly coinciding with the 

 lower O, at 55* of temperature. 



The whole interval from .806 to 1.000, comprehending the 

 fpecific gravities of all fpirituous compounds, is in this manner 

 divided into five nearly equal portions, each of which, com- 

 prizing from .038 to .040, is meafured by the whole length of each length of 

 the ftem ; fo that each of the 54 intervals on its face corref- [ bc ? e m u m{ ""' 



ing to about .04J 

 ponds to considerably lefs than an unit in the third place of the and each divi- 



i'pecific gravity, and indicates a difference of about one half fion to left than 



. . .0011nfpec.gr. 



per cent, or two quarts in 100 gallons, in the quality of the or i percent, in 



compound, and the inftrument is therefore abundantly fen- ft « n fith. 



iible to very minute variations in thefe refpeds. 



With regard to the application of the weights, no error can 

 poflibly be committed. If the inftrument floats in any liquor, 

 fo that its furface cuts any part of the ftem, it is properly- 

 loaded. Any weight but the proper one will either fink it 

 entirely, or fuffer the ftem to rife totally above the fluid. 



The fpecific gravity indicated by any divifion on the ftem Spec. gr. indi- 

 of the hydrometer, is feen inftantly by reference to a Hiding- cated by the di- 

 rule belonging to it, whofe two faces are (hewn, plate XV. ften^compared 

 fig. 2 and 3, on which the lines of divitions A A, A A, marked w 'th the rule.' 

 with the letters of the alphabet, reprelent thofe on the inftru- 

 ment when loaded with the weight, whofe number is marked 

 over the O at the commencement of each feries, and the exte- 

 rior lines of divifions B B, B B, near its edges, fhew the corres- 

 ponding fpecific gravities compared with that of water at 55°. 



In order, however, to afcertain the ftrength and value of the Correction for 

 fpirit, it is neceifary to examine its temperature and apply the temperature ap- 

 proper correction, which is done with extreme accuracy by the p 1C ' 

 fame fliding-rule, by an ingenious application of two fcales of 

 unequal parts to each other, viz. the lines C C, C C, marked 

 *' Atkins/* and the lines A A, A A, marked with the letters of 

 the alphabet. The mode of doing this is as follows : the tem- by f ett j ng an ; n _ 

 perature of the liquor being taken by the thermometer accom- clex on the Aider 

 panying the inftrument, the afterifk or index, plate XV. fig. 1, ternpertu^f 



on fliewn by the 



thermometer. 



