JO ABSOLUTE ATOMIC WEIGHT. 



Frequency of Circulation. 



The oldest Half Eagle in this lot was of 1857, the latest 

 of 1901. The entire period comprises 45 years. 



How remarkably varied the frequency of the coin is, we 

 found again for gold as we have found it for silver. 



The year 1880 was represented by 9 coins, 1895 by S; 

 these two years by 17 coins out of 102. 



The year 1881 was represented by 20 coins, the year 1897 

 by 21 coins; these two years represented 41 coins out of a 

 total of 102. 



The three years: 1880, 1881 and 1897 were represented by 

 50 coins. In other words, these three years had furnished 

 half of all coins in local circulation ; as many as the other 

 42 years taken together! 



Amount of Abrasion. 



The great frequence of the coins of the two years iSSi 

 and 1897 permits us to obtain an estimate of the amount of 

 abrasion. 



But upon looking over the record of the individual 

 weights of the Half Eagles of 1897 we find one decidedly 

 under-weight, namely 8.235 only. This exceptionally 

 "worn" coin must, therefore, be laid aside. The twenty 

 remaining coins of 1897 range from 8.322 to 8.370, and give 

 a mean weight of 8.357. 



The twenty Half Eagles of 1881 run from 8.300 to 8.356 

 and give a mean of 8.333. 



Hence, in the 16 years from 1881 to 1897, the mean wear 

 of 20 Half Eagles has amounted to 24 milligrammes, which 

 is i% milligramme per year. 



Therefore, a new Half Eagle, in 1901 should weigh about 

 4/12 m g r< more than the mean for 1897; that is 8.361 

 grammes; for those of 1897 have only been 3 years in circu- 

 lation. 



We have obtained only one single Half Eagle of 1901 ; it 

 vreighed 8.356 grammes, but of course, had lost some by 

 abrasion of perhaps half a year. Besides, the mint cannot 

 produce the coin equal, even of gold, to the milligramme. 



