Prof. Miller on the Imperial Standard Pound, 5^ 



the weight of a cubic inch of water weighed in a certain manner. 

 The Commissioners, however, in their Report dated December 21, 

 1841, decline to recommend the adoption of these provisions for the 

 following reasons : '' Since the passing of the said Act it has been 

 ascertained that several elements of reduction of the pendulum expe- 

 riment therein referred to are doubtful or erroneous. It is evident, 

 therefore, that the course prescribed by the Act would not necessarily 

 lEcproduce the length of the original yard. It appears also that the 

 alietermination of the weight of a cubic inch of water is yet doubtful 

 (the greatest difference between the best English, French, Austrian, 

 Swedish and Russian determinations being about y-joo °^ ^^® 

 ,:vhole weight, whereas the mere operation of weighing may be 

 •performed to the accuracy of j-^^^ of the whole weight). Several 

 measures, however, exist, which were most carefully compared with 

 the former standard yard ; and several metallic weights exist which 

 were most accurately compared with the former standard pound; 

 and by the use of these the values of the original standards can be 

 respectively restored without sensible error. And we are fully per- 

 suaded that, with reasonable precautions, it will always be possible 

 to provide for the accurate restoration of standards by means of 

 material copies which have been carefully compared with them, 

 more securely than by experiments referring to natural constants." 

 '•■ At the end of the Travaux de la Commission pour fixer les Me- 

 asures et les Poids de 1' Empire de Russie, Professor Kupifer has col- 

 lected the results of observations made in France, England, Sweden, 

 Austria and Russia for finding the weight of a given volume of 

 water. The resulting values of the weight of an English cubic inch 

 of water in a vacuum at 62° Fahr., expressed in doli, of which 

 1/22504-86 make a kilogramme, are as follows : — ;^.(/3 ^bch 



-If!.' ^ French observations 368*365 ^I'psgnoo 



Enghsh observations 368-542 .Bsq^^ 



-V^ bn£- atg-wedish observations ..... pS^m^'' 368'474'too A 

 klgil 1o Austrian observatioris-^^^^. li^^ii^^loj.^ ^i/8; 368-237 oq eI&^z 

 Mi^yy^n^ Russian observations./^';'. '.-^l l^t'f . [Q^ 368-361 r-'?>'^"fT 

 ^'A^ssuming the Russian observations to be the best, as they probably 

 are, it will be seen that a troy pound deduced according to the method 

 prescribed by the Act, would be 2-829 grains too heavy ; while, if the 

 Austrian observations had been accepted as the best, the troy pound 

 would have been 4-707 grains too heavy. On the other hand, it 

 was possible to recover the weight of the lost standard in air to 

 within a fraction of 0*001 grain, by means of the troy pounds which 

 j<had been compared with it, and could be easily brought together for 

 ^'^tecomparison. Seeing, then, that the error of one of these two me- 

 thods of restoring the lost standard, is at least 2829 times as large 

 as the error of the other method, the Committee could not hesitate 

 {.to recommend the adoption of the latter. 



' A Committee was appointed by a Treasury Minute of June 20, 

 1 843, to carry out the recommendations contained in the Report re- 

 ferred to above. The evidence for ascertauaing the weight of the lost 

 standard, placed at the service of this Committee, consisted of the 



