56 
Iron * 
of the iron in the ore, and denominates the metal contain- 
ed in such and such an ore to be “ strong, coarse, ill-melt- 
ing iron or “ weak, tender iron, possessing no body.” 
That iron-stones and ores yield, in the operation of 
smelting, different qualities of crude iron, as to strength, 
is an undeniable fact ; and that the same variety attaches 
to iron when converted to malleability is a truth daily evin- 
ced in our forges : yet these facts by no means entitle us 
to conclude, without farther investigation, that these va- 
rieties of strength are the hereditary property of the pris- 
tine formation of the metal. This inference accords with 
a hasty view of the matter, and a bare comprehension of 
effects, without tracing to its source the modifying prim 
ciple of the whole. The theory which I have adopted, 
and which in every step I have found supported by nume- 
rous experiments, upon different scales, and by a long 
course of practical observation, explains to me, with 
much more ease and harmony, the whole phenomena of 
quality in ores and iron-stones. 
To illustrate that part of my theory relative to strength, 
let the preceding experiment, wherein carbonated crude 
iron was produced from the oxyde of pure iron, be repeat- 
ed with the addition of a little pure clay. If the clay ad- 
ded be half the weight of the lime also used, the iron will 
be found, when subjected to the gauge, much superior 
in strength ; and if the experiment be accurately perform- 
ed, the metal will be but a little reduced in point of 
carbonation. The following proportions will give accu- 
racy to the result Oxyde of iron, 4 parts— Lime, 2—* 
Clay, 1 — Glass, 3 == 10 parts. By mixing clay with 
the flux in all experiments, the strength of the crude iron 
is improved. This point may be urged so far as to form, 
by an extra-addition of clay, a flux of difficult fusion ; in 
which the iron becomes suspended in globules, which ^ re 
partially malleabilised apart from each oilier. Crude iron, 
