must play an important part in the mechanical processes ol — 
change, and constitute one mechanical feature of the substances 
thus specially affected. 
nother evidence that the ultimate molecule bas the prop- 
body of minute quantities of other substances (e. g., the great 
changes in the tenacity and other properties of steel, attendant 
on slight variations in the percentage of carbon associated with 
the iron; and in the tenacity of iron or steel resulting from 
slight differences in the percentage of manganese, phosphorus, — 
ete.) According to the results of the experiments of Kirkaldy 
on Fagersta steel (Sweden), the union of 0°5 per cent (or giv) 
of carbon with the iron augmented the tenacity of the ham- 
mered bars from 4 to }, and an increase in the quantity of 
Johnson’s Cyclopedia, by Mr. A. L. Holley, gives the compara- 
tive effects on the mechanical qualities of steel of several differ- 
Fagersta (Sweden), Neuburg (Austria). 
i | per centage of 
Serban.” | AY Bsgales | Fekete °f) Rania! | AY dod. | "Breteine. 
ae Pe EES EES: * 
Tbs. per 3q. in. ibs. per sq. in. 
1-00 p. c. | 126, 486 to l2 to6p.c. | 0°88 to 1:12 | 126,486 to | 5p. ¢ 
46, 383 149, 226 
0°70 p. c. | 100,905to |4to6p.c. | 0°62 to 0°88 | 103, 747 to | 5 to 10p.% 
30, 126, 486 
0°45 p.c. | 99,404to [9tol0p.c. | 0°38 to 0°62 | 80, 298 to | 10 to 20p.¢ 
03,747. | 103,747 
0°35 p.c. | 68, 217 to |12 p. c. 0°15 to 0°38 | 68,217 to | 20 to 25 p.& 
, 638 80, 298 
0:30 p.c. | 59,690 to /11to22p.c. | 0°05 to 0°15 | 56, 848 to | 26 to 30 p. % 
62, 533 Vhs ee 
68, 217 
It will be seen that with the Fagersta steel an increase in the 
proportion of carbon from 0°30 of 1 per cent to 1 per cent (or 
ris) more than doubled the tenacity ; and that with the New 
