'|^» On the Strenglhs cflht Mixtutes of Alcohol. 



loOiOOO, and that the difference or interval upon the ftem between the interfe£\Ion ty the 

 furface of the fluid in the firfl: and in the laft fituation, (hall be taken as a fcale of looa 

 parts ; and of thefe parts the requifite portions being fet off from the table upon the ftem, 

 as marked Fig. i. PI. XVIII. the inftrument is then ready for ufe. 



.It feems almoft unneceflary to remark, that the fcale upon the ftem muft be read upon 

 that vertical line which is marked with the temperature which a thermometer fhews the 

 :fluid to poflefs. The inclined crofs line, which interfedts at the fame place that vertical 

 line and the furface of the fluid, is marked with the number denoting the proportion of 

 alcohol contained in looo parts of the fluid. The redu£lion of this refult to any defired 

 (Irength or proof, of which the proportions of alcohol and water are known, will be eafy to " 

 moft arithmeticians, but would extend our limits too far if examples were to be given 

 here. 



ef the inftrument. Hence by a rough calculation, if the length of the ftem be about five times the diameter 

 of the ball, the diameter of the ftem will prove about one-fixth part of the diameter of the ball. 



It is not neceflary to prepare two fluids of the precife denfities above mentioned in order to find the in- 

 terval, as it may eafily be had from any' two fluids whatever. Thus, if v»ater at lOoo, and alcohol at S40, 



■ 1000—840 160 1600 



were ufed, the interval on the ftem would be denoted by or or of the portion 



1000 1000 1 0000 



moft deeply immerfed, which are nearly the divifions of the table. Or, if a fingle fluid be prefered, then— - 



I. Weigh the whole inftrument fui'pended to the dilh of a pair of fcales. 2. Find the apparent lols the in- 



^rument fuffcrs by immerfion in water, with a load or ballaft attached to it, of which the refidual weight is 



known, and can be allowed for. This immerfion muft be adjufted to the upper divifion of the ftem. 



3. Place a weight in the oppofite fcale, equal to one-fifth of that apparent lofs. The inftrument will rife, 



»nd the furface of the w.iter will interfedl a point at the diftance of »ooo divifions below the firft. 4. Or if 



•ny fubdivifion of that fifth part be put into the fcale, the rife of the ftem will be a proportionst* part of 



»eoo.— W. N. 



