ON THE MANUFACTURE OF IRON. 755 
charging, and 665° when ready for its charge, or a mean of 517°; the reduc- 
tion of something like 200° being due, no doubt, to the increased burden 
which this higher furnace was actually carrying. 
Economy of fuel in the blast-furnace is of twofold importance: first, from 
its direct action in reducing the cost of making iron; and secondly, as the 
superiority of quality possessed by charcoal iron over that smelted by pit 
coal consists, in all probability, in the greater amount of impurity contained 
in the latter description of fuel, it obviously becomes a matter of consideration 
to employ as small a quantity of coke as possible, so as to diminish the weight 
of foreign matter introduced into the furnace. Hence any system inter- 
fering with these conditions requires close and careful watching on the part 
of the ironmaster. 
Magnetic Ironstone of Rosedale Abbey.—Hitherto our observations have 
been confined chiefly to describing the natural and metallurgical features of 
the Main bed of ironstone in Cleveland; but as there are some matters of 
interest connected with the Top Seam, a short notice of it here may not be 
out of place. 
This seam of the Lias formation (which is either the Top seam, or very near 
its geological position) has been wrought in two or three places, but by far 
the most important workings are the mines at Rosedale Abbey. The samples 
1 and 2 are analyses of the Rosedale Abbey ironstone. No. 3 is the Top 
seam from Ingleby. 
No. 1. No. 2. No. 3. 
Blackstone. Se oe Ingleby. O 
: : ; e os 1° 
Oxide of iron ... ao 64°90 ae { ba Fe? 02 ... yee Fe? 038 
Do. manganese... — 69 ste "94. 
Alumina... oc 582 9°25 4 Cane A 4°71 
ATG "oe or 3°53 fon ‘2°86 oe 3°32 
Magnesia ae. eee "99 +? — Wee 3°34 
Potash cee ay _— trace ee *20 
Carbonic acid — 10°36 26°00 
Silica de sf ao 5°70 sc 6°95 a 7°37 
Loss by heat... Hee 16°15 ae 1°59 ae — 
Sulphur ... ras oe -- "03 “08 
Phosphoric acid... = I°41 1°36 
Carbonaceous = "34 “38 
Water — 3°76 3°86 
100°52 98°16 99°77 
Authorities............ W.Crowder _J. Pattinson. Clarence Laboratory. 
Metalliciron ... ore 45°43 as 49°20 ec 36°95 
The Rosedale stone is chiefly smelted at Ferry Hill furnaces, and to some 
extent as a mixture at other works. In quality the iron is much like that 
which is obtained from the main beds of ironstone. 
The Ingleby stone is a portion of the Top seam, and, being thin and expen- 
sive to work, is now abandoned. A few hundred tons were smelted without 
admixture at the Clarence Works. The content of iron was verified as being 
superior to the ordinary Cleveland main seam, but the metal in quality did 
not differ from the usual make of the district. 
Weardale Ores.—The Weardale ores, from the quality of iron produced by 
their use, require some separate notice. They are found in the veins of the 
mountain limestone, either as sparry or spathose carbonates, or as hydrated 
peroxides ; the latter, no doubt, resulting from the joint effects of atmospheric 
*and aqueous action on the former. The following information, communicated 
by Mr. Attwood, shows the composition of both varieties :— 
3c¢2 
