Obfervations on Tron and Stecl. 13 
into cold water. I hall therefore fuppofe he meant to fay, 
that the oxygen of the decompofed water partially united 
with the hot metal: this, without further explanation, 
would be ftill very unfatisfaétory ; fince it does not {pecify 
the modification of the metal operated upon. Plunge very 
hot malleable iron into cold water, and pastef the water 
will be decompofed ; its oxygen will unite with a portion of 
the iron; this portion, however, will be: found to have 
feparated from the bar or mafs, to have loft its metallic 
brilliancy and weight, and to have pafled into the ftate of 4 
black oxyde. Similar phenomena ‘take’ place in treating 
fteel after the fame manner. Crude iron is lefs fufceptble 
of changing its metallic fra¢ture by fuch treatment ; ‘though 
it is rendered very infufible by the expulfion of its carbon. 
Mr. C. fays that “ blaft furnaces are like two four-fided 
pyramids’ jomed bafe to-bafe 3°’ Mr. Chaptal fays the fame 
thing, and fuch I queftion not may be their fhape in France: 
In Britain however they are entirely conical, excepting:6 or 
7 feet at the under end, which forms a fquare funnel: 
more juft idea of the figure would be conveyed by comparing 
them to two inverted cones, the bafe of the larger refting 
upon thatiof the {maller. | 
© In charging the furnace Mr. Collier has forgot to mention 
the principal material, and its’ proportions, viz. the ore, 
and erroneoufly ftates, that ‘* equal portions of coal cinder 
and lime-ftone” are introduced, without even mentioning 
whether thefe proportions are by meafure or weight... The 
proportions of ore, coal, and lime-ftone, are very various at 
different: works; the whole depending upon;an intimate 
union and knowledge of the quantity and quality ‘of the 
various principles and fubftances contained in each: the 
proportion” of materials befides is yaried at» pleafure, to 
produce the quality of crude iron wanted. ob 
At fome works the quantity of lime ufed as)r to’ 3 0f 
cinders by weight, but this is an exceflive: proportions and 
‘is Cintas neceflary to correct. the impuritiescoffome iran- 
. tones 3 : 
