COMPARISON OF ^ WITH PC No. 1+PC No. 2 + B + V + 0-03 gr. 
893 
By a mean of 286 comparisons of T with Sp in January ... August, 1845, 
Tii:Sp+0'00073 grain in air (^= 13*74, 6 = 758*91). ^;T—^;Sp= volume of 0*26 grain 
of water = volume of 0*00032 grain of air. Therefore T=Sp4-0*00105 grain. If 
1=7000*00000 grains, T=5759*47067 grains, and therefore Sp=5759*46962 grains. 
According to the account in manuscript of Professor Schumacher’s comparisons of 
his kilogramme ^ with his troy pound Sp, by the observations of December 1831 
and October 1835, 15433*77226 grains, of which Sp contains 5760. After these 
comparisons ^ lost a portion of its substance, and became 0 02557 grain lighter; 
for by a mean of forty comparisons by Petersen in March 1837, and thirty-six com- 
parisons by Captain v. Nehus in February and March 1837, ^=15433*74669 grains, 
of which Sp contains 5760. Hence, in 1837, ^=15432*32555 grains, of which I con- 
tains 7000*00000. In Steinheil’s Memoir, “ Ueber das Bergkrystall-Kilogramm,” 
(p. 168), the following passage occurs; “ Conferenzrath Schumacher erhielt eine 
Platina-Copie des Archivkilogrammes, welche, zufolge sorgfaltiger Abwagungen des 
Professor Olufsen aus Koppenhagen im April 1835 (siehe Jahrbuch fiir 1856 von 
Schumacher, p. 250) leichter war als das Archivkilogramm um 0*41 Milligrammen. 
Aus Unvorsichtigkeit eines Mechanikus wurde diese Copie spater abgewaschen und 
hatte dadurch an Gewicht verloren. Um zu bestimmen, wie viel dieser Verlust 
betrug, wiederholte ich im Jahr 1837 die Vergleichung der Schumacher’schen Copie 
mit dem Normalkilogramm der Archive und es ergab sich, dass es nun 1*59 Milli- 
grammen leichter war, also 1*09 Milligrammen an Gewicht durch die Operation des 
Abwaschens verloren hatte.” The most probable explanation that can be offered of 
the discrepancy contained in these words, is that by an error of the press, 1*59 was 
substituted for 1*50. According to Kupffer, however (Travaux de la Commission 
pour fixer les mesures et les poids de I’Empire de Russie, t. ii. p. 413), the value of 
^ is 1*592 milligramme. Supposing that in 1837, ^—^=1*50 milligramme 
=0 02315 gr., then 91= 15432*34870 grs. If ^—^=1*59 milligramme =0*02454 gr., 
a=15432*.35009 grains. 
By the observations of 1831 and 1835, ^= 15432*351 12 grains, of which Icon- 
tains 7000*00000. If in April 1835, ^—^ = 0*41 milligramme =0*00633 grain, 
91= 15432*35745 grains. This difference of 0*00875 grain in the weight of 91 between 
1835 and 1837, is difficult to account for, unless due to an accumulation of dust since 
wiped off; for it cannot be supposed that a weight so carefully preserved as the 
kilogramme des Archives, could have lost nearly 0*01 grain of its substance in the 
course of two years. 
All the other comparisons, in which the number of observations is large, yield 
results sufficiently accordant with the value of 91 deduced from the comparisons of 
with (25, and of (25 with I-f-K-fA, I-bL-f-B, I-j-M-t-F, I-j-N-l-A, which gave, — 
Kilogramme des Archives =15432*34874 grains, of which the new platinum 
standard pound contains 7000. Or, kilogramme des Archives = (2*20462125) standard 
platinum lb. Standard platinum lb. =453*5926525 grammes, of which the kilo- 
gramme des Archives contains 1000. 
6 A 2 
