o Standard of Weight and Meafure. 



Add the corredion foi' the Icfs of weight of the four wires, by being! 



It inch deeper immerfed in the water, than when the counterpoife was> = -f 

 adjufted _ - - - - j 



149 



0,05* 



Corre6ted weight of the cylinder in water _ _ - _ — 2549,15 



After this experiment, I difcovered that fome fmall bubbles of air had infinuated themfelves 

 between the cylinder and the fcale in which it hung ; thefe therefore were removed, and the 

 experiment repeated, as follows : . 



* In order that this and fome other corrcftions may be the more eafily applied, I have computed the three 

 following tables, to be ufed whenever great accuracy is required. 

 Table I. Shewing the expanfion of caft brafs, both in length and folidity, and alfo of water, in folidity, by 



the effcft of heat : the former i» derived fron Mr. Smeaton's experiments (Phil. Tranf. vol. XLVIII.); 



»nd the latter from fome of my own, when I was a refidcnt member'of the univerfity of Oxford. 



Table II. Shewing the correftion for the 

 uires, or the diminution of the weight of 

 the water-fcales, by immetfion in water. 



Table III. Shewing the correftion of the weight of the 

 fphere in air, on account of the weight, or heat, of the 

 atmofpiicrc. 



N. B. 80 inches in length, of the wirAl 

 for the fcales for the cube and cylin- > f^^* 

 der weigh - - 3^''^ 



therefore I inch will be ,077 grain, 7 



and 4 wires of i inch - i ~ Oi3C» 



Alfo, 9 1 inches of the wire for the V _ 

 fphere weigh - 5 — -°>'?' 



and I inch = 0,227, and 3 wires of 7 ,0 



I inch - . 5 = °'<^^3 



and the fpecific gravity of the wire is = 8,7 • 



Vol. III. — ^JuLY 1799. 



Water being taken a* heavier than air, as 836 : i (fee 

 Obfervations in Savoy, Phil. Tranf. for 1777), the baro- 

 meter being at 29,27, and thermometer 51', a fphere of 

 air equal in bulk to the brafs fphere, viz. = 113! cubic 

 inches, would'weigh, when the barometer was 29,5 

 inches, and the thermometer 500 = 34,57 grains; 

 and I cubic inch of fuch air = ©,304 



This correftion will ferve for any other body whofe bulk 

 is known. 



X 



No. 



