ERRORS OF WEIGHING. 45 



Upon putting my question in the most modest form as a 

 request for information, I was informed that these specific 

 gravities were calculated by means of seven place logarithms. 



Seriously and most earnestly I here am compelled to 

 declare, that much of the vaunted high accuracy of the 

 so-called exact science of to-day in our laboratories, our 

 publications and our academies of sciences, sciences has no 

 better foundation in nature or fact than had the last four of 

 the seven decimals given in beautiful and distinct writing on 

 the labels of common building stones in one of the military 

 science shops of the great United States of America. 



True and Sham Accuracy. 



But if we would lift the fog that has settled over the true 

 values of the fundamental data of chemistry, the atomic 

 weights of the elements, since the first publication of the 

 misleading and muddled work of Stas, we must learn to dis- 

 tinguish between true accuracy and sham accuracy. 



We must again rely on the chemist and not merely on 

 the balance and the weights. 



If Ramsay, with the finest balance oscillating to the ten 

 millionth of the gramme, did not get as good and true a 

 chemical result as did Berzilius eighty years earlier by 

 means of a balance not better than the prescription balance 

 of common American drug stores, we must cease to judge 

 by the apparatus and again demand the work of a true 

 chemist. 



The Number of Decimals. 



And how shall we limit our number of decimals in the 

 calculation? 



Any one can answer this question, both theoretically and 

 practically. 



The theoretical answer can be readily given by our gen- 

 eral mode of calculation stated before. See pp. 29-32. 



The practical answer in this case is the simplest possible. 

 It is useless to give more decimals than one beyond the first 

 varying digit. 



