154 On the Weight of a Cubic Decimetre of Water. [Dec. 5, 



Five weighings in water gave, according to Mr. Chaney's observa- 

 tions and my reductions : — 



. Temperature of 

 water, t. 



Apparent weignt ot 

 S in water at t°, 

 in grains. 



W eignti ox Dis- 

 placed water at t, 

 in grains, p t - 



W eignt ot dis- 

 placed water at 

 56-20° F., according 

 to formula V, 

 P 56 . 20 , in grains. 



1. 54 -58° F. 



-27*02 



28467-80 



28466 -07 



2. 54 -72 



-27 -01 



28467 -79 



28466 -21 



3. 56 63 



-24*70 



28465 -48 



28466-11 



4. 57 '60 



-23 -72 



28464 -43 



28466-11 



5, 57-48 



-23 *65 



28464 -50 



28466-29 



The numbers of the column Y are calculated in the same manner 

 as for the cylinder C, namely, according to the formula : — 



p p t 0-999 36 9 . Y 56 . 2 



The close coincidence between all obtained values of P 56 . 2 shows 

 that all the data for S deserve full confidence, which fact Mr. Chaney 

 also fully recognises, and we therefore take the general mean : 

 P 56 . 2 = 28466-16 grains. 



The volume of S at 56'2° F. = Y 56 . 2 = 112 64972, and therefore 

 the weight, in vacuo, of a cubic decimetre of water at 4° C. = 

 999-8546 grams. 



As this result is close to the two preceding, we may take a general 

 mean from the three, giving to each of them a weight proportional to 

 the product of the number of weighings and the volume of displaced 

 water, that is to say, proportional to the mass of weighed water : — 





Number 

 of 



weighings, 

 n. 



Approximate 

 volume, in 

 cubic deci- 

 metres, p. 



Product, 

 np. 



Weight of a 

 cubic decimetre 

 of water at 4°, 



in vacuo, in 

 grams. 



Large cylinder, Kupffer. . 



20 

 2 

 5 



0-818 

 9-39 

 1 -84 



16-36 

 18 -78 

 9 20 



999 -8495 x 9 

 999 -8414 x 10 

 999 '8546 x 5 



From these data we find the most probable weight, in vacuo, of a 

 cubic decimetre o.' water at its maximum density to be 



999-847 grams. 



