Obfervations on Iron and Steel. 15 
manner not eafily to be underftood. Dr. Beddoes has lately 
given a more accurate detail of the various phenomena ex- 
hibited during that operation*. 
The fubftitution of large rollers, in place of the ftamping- 
hammer, is well calculated to overcome a large quantity of 
iron, and for impofing on the bar a beautiful finifh, efpe- 
cially if afterwatds paffed under a {mall tilt-hammer; but 
the quality of the iron mutt {till be inferior to that manu- 
fa€tured with heavy harnmers. The compreffion of the bar, 
on all fides, when paffing through the grooved rollers, muft 
tend to enfold, rather than expel, a portion of the flug; 
whereas the heavy blows of a hammer, which with the helve 
weighs from 3 to 4ooolb. cannot fail more entirely to diffi- 
pate all the fubftances fufed in contaé with the iron, and to 
give a degree of fibre and tenacity not to be acquired ii a 
regular and continued preffure. . 
Numerous and diverfified are the opinions refpeéting the 
exifting caufes, which conftitute the very great difference, 
in quality, between the bar iron manufaétured in Great 
Britain, and that made in Sweden, Siberia, Spain, &c. 1 
have reafon to imagine that this difference arifes neither 
from the ruft, acquired by the iron being laid in damp 
places, nor yet from the fuperior richnefs of the foreign ores. 
In Siberia and Sweden the iron is pufhed off to market at 
ftated periods, and becomes comparatively old kept, merely 
from the great diftance it has to travel before it can reach a 
market. Mr. Collier feems inclined to impute this fupe- 
riority to a greater quantity of iron contained in the ore; 
and to its being more deftitute of mixtures: hence he ftates 
the average of the Swedith ores to be 70 pounds pure iron— 
erude iron he muft mean—in the hundred, and Englifh ores 
30 to 40. I have feen many-of the northern ores, fome of 
them very rich in iron, equal to 65 and 70 per cent.; but 
many more of them not yielding beyond 40, and fome of 
them as low as 20. Norwegian ore from the mine of Horke- 
* Dr. Beddoes’s paper fhall be given in a future Number. 
Dhat- 
