30 THE ERRORS OF PRECISION. 



To state as experimentally established, as data of labor- 

 atory work, numbers and decimals that are merely and 

 absolutely fancy, is about as disgusting and reprehensible an 

 act as can be committed against the true progress of science. 



Edgar F. Smith and W. L. Hardin. 



Still I shall here take the special example for illustration 

 from the laboratory of Edgar F. Smith of the University of 

 Pennsylvania, because it was published in the Thesis of 

 Willet Lepley Hardin in 1896, and in various Journals, after 

 the error had been fully shown by me in letters to Professor 

 Smith in May, 1895. 



We take then, as special case for the study of the first 

 great common error in calculation of atomic weight deter- 

 minations, the six electrolyses of mercuric oxide made by 

 W. L. Hardin in the laboratory of Edgar F. Smith. 



The mercuric oxide taken and the mercury obtained are 

 the weighed quantities. The weighings are given to the 

 hundredth of a milligramme (by oscillation method). 



Accordingly, the hundredth of the milligramme being 

 the last figure determined, is simply the nearest full number 

 of that place, and subject to the usual limitation of a 

 possible error of at most half a unit. In other words, the 

 utmost that can be claimed is that the weighings given are 

 subject to an uncertainty of half a hundredth of a milli- 

 gramme, or half a unit in the fifth place of the gramme. 



For each of his six determinations Mr. Hardin calculates 

 the corresponding atomic weight, and gives the results with 

 two decimals (Thesis, p. 23). The weighings and the cal- 

 culated atomic weights are identically the same communi- 

 cated to me in May, 1895, by the courtesy of Prof. Smith. 



But the weighings do not sustain any such atomic weights, 

 and the publication of these atomic weights as experimental 

 data is false in fact and fraudulent in nature. 



Taking Hg at 200, the oxide exceeds the metal by exactly 

 S per cent. Taking the mercury as reported by Hardin, and 

 adding 8 per cent thereto, we obtain exactly the weight of 



