MAGNESIUM. SCHEERER. Ill 



These " probable errors " are given by Clarke on page 

 144 of the American Chemical Olla Podrida as 200, 43, 13, 

 3 millionthsper unit of weight operated upon. 



The squares hereof are therefore 400 oo, 1849, J ^9 and 9 

 units in the izth place or the millionth of millionths of the 

 gramme, per gramme operated upon. 



In passing, we may state that Richards and Parker gen- 

 erally used less than two grammes of their pure magnesium 

 chloride (they suppose, for it cannot be weighed accurately) ; 

 never as much as 3 grammes. 



Taking the relative values only, and putting the skill and 

 perfection of the work of Richards in his third series at one 

 million, we find according to the process of this same Olla 

 Podrida Americana, the skill of the others given as follows : 

 Richards and Parker, IV Series, 1,000 ooo 

 " " " III " 52 632 



" II " 4 878 



Dumas, 1860 only 225 



As this table of perfection is not quite readily grasped, 

 we will reverse it. 



We will put the skill and ability of the great French 

 Chemist Dumas, as one and calculate the skill of the 

 Harvard Chemists in that unit. 



In this way, the above figures will present : 



Skill. 



Chemist Dumas, 1860, i 



Harvard Chemists, II Series, 17.5 

 " " III " 210 



" " IV 4,000 



The chemists of Harvard, "Richards and Parker," 

 started out in this atomic weight determination twenty times 

 more perfect in their work and methods, than was Dumas 

 almost at the height of his fame. 



Well, we may put this twenty to the credit of Modern 

 Chemistry and America; and the modest young American 

 Chemist may not protest. The Present and America is the 

 pedestal on which they proudly stand. 



But just note the wonderful capacity for progress in the 

 work of these young chemists of Old Harvard. 



