AND RATIO OF THKIK ATOMIC WEKJUTS. 45 



That this is the case may be seen tVoin many ilhistrations in my note-books. 

 I cive one in which the globes counterpoised against eacii other were ))otli closed 

 by fusion, so that their true difference of weight was constant. The volumes were 

 equal on the two sides of the balance, and were 15.77 litres. 



TABLE SHOWINC. THE ELIMINATION OF THE EKI'TUrr IIK AIK CURRENIS : 



12.45 P.M. 41.81893 



It will be observed that, although successive weighings differ two oi- three 

 tenths of a milligramme, the means of pairs of successive weighings agree as well as 

 could be desired. 



27. CX'TGEN BY SECOND .METHOD. CHANGE OF SURFACES OF GLOBES. 



In this series of experiments, the surfaces of the globes were not touched dur- 

 ing the determination of the weight of the globe when empty and that of its weight 

 when filled with o.xygeu. In one case, seven successive experiments were finished 

 without touching the globe. Commonly, some trifling accident or the necessity of 

 renewing the lubrication of the stopcock changed the weight of the globe or of its 

 counterpoise ; in the series of seven detei'miiiations just mentioned, the difference 

 between the weight of the globe and of its counterpoise was determined three times, 

 and the agreement was good. 



Although changes in the surface of the globe or of its counterpoi.se were not 

 to be feared in this series of experiments, it was thought worth while to determine 

 the amount of the changes which might be expected if cleaning were necessary. 

 To eliminate erroi's which might be caused by changes in the lubrication or by 

 leakage, two globes were used which had been closed by fusion. To one of them 

 was added a flask, also closed by fusion, so as to make the volumes of the masses 

 on the two pans of the balance equal ; each measured 15.7667 litres. 



The globes had been standing in the balance room for a year. For the fii'st 

 expei'imeut, both were moistened l)y breathing on them and wiped with a dry 



