W. A. Norton—- Variability of the Ultimate Molecule. 189 
burg steel an increase in the proportion of carbon from 0°15 
per cent to 1°12 per cent (or about y}s) augmented the tena- 
city in the ratio of 2} to 1. 
It has been shown by recent experiments* that an increase 
in the percentage of manganese in Bessemer steel from 0°5 
per cent to 1 per cent, while the percentage of carbon and phos- 
phorus remain the same, may augment the tenacity of the steel, 
when untempered, by one-fifth, and when tempered in oil 
one-quarter. In this case but one molecule of manganese is 
added to every two hundred molecules of iron. 
The magnitude of these variations of tenacity is greatly dis- 
proportionate to the quantity of carbon, or manganese, associated 
with the iron. Nor can such mechanical effects, increasing 
progressively with the percentage of the ingredient, be reason- 
ably attributed to continued variations in the number of atoms 
property of variability, are furnished by certain facts in Chem- 
tcal Physics. i 
(1.) In solution, solids assume the mechanical properties of 
liquids. The entire mass of the solution is in the liquid state, 
ical composition. The natural inference then is, that they have 
experienced a change of mechanical condition. The alterna- 
* On the Effects of Phosphorus and Manganese on the Mechanical Properties 
oe Steel; by M. Euverte (Van Nostrand’s Engineering Magazine, April, 1878, p. 
3, ete.). 
