alia tial 
a a 
ON STRENGTH AND PROPERTIES OF CAST IRON. 379 
After the request of the Association, expressed to Mr. Hodg- 
kinson and myself, that an inquiry should be instituted into the 
comparative merits of iron made from hot and cold blast, nearly 
ten months elapsed before the necessary materials could be ob- 
tained. In fact, the experiments would have been of the most 
meagre description, for want of samples, but for the friendly co- 
operation and assistance of Mr. Murray, of the Monkland Iron 
Works. To that gentleman we are indebted for the whole of the 
Scotch irons, exclusive of other valuable information relative to 
the fuel and analysis of the ores; I have therefore great plea- 
sure in thus publicly expressing my acknowledgments. 
Before entering upon the experiments, I made application to 
the greater part of the works from whence iron was received, 
for information relative to the nature of the ores, fuel, flux, &c. ; 
also for such analyses as the proprietors might be enabled or 
disposed to furnish, including the temperature of the air used in 
the process of smelting. 
To these inquiries I received replies which, although of great 
importance in themselves, could not with propriety be intro- 
duced into this report.* 
During the progress of the investigation, it was found desi- 
rable for Mr. Hodgkinson and myself to divide our labours ; 
and in order to examine the different irons with the utmost 
care, the experiments were classed and apportioned in the man- 
ner described in Mr. Hodgkinson’s report. 
This division was attended with considerable benefit, as it ex- 
cited a closer investigation of the subject ; and the whole of the 
experiments being made at my works, gave a facility for com- 
parison that could not otherwise be obtained. 
* Mr. Murray, of the Monkland Iron Works, has, however, supplied me 
with the following particulars relative to the Scotch irons, viz. the Carron and 
Devon irons, which are derived, like most of the Scotch metals, from argillaceous 
carbonate of iron, and are found in the coal-basins of the country. Some of 
the poorer ores are found in balls imbedded in argillaceous schistus, and worked 
or turned out with the coal; but the principal is a seam of black hand, at a 
depth of 15 to 25 fathoms under the splint, or fifth seam of coal, of the Lanark- 
shire basin. This iron-stone varies from 9 to 15 inches in thickness, and con- 
tains from 35 to 40 per cent. of iron. Two-thirds of this ore is generally used 
to each charge, and one-third of the poorer balls and bands containing from 
20 to 25 per cent.—Dr. Colquhoun analyzed the black band ore, whicn gave 
_ Carbonic acid....... bencadatghep eased sa WIUIING « odescaceucsqatecssocatavseapecUroa 
Protoxide Of i0N.....sceeeeseeeee 53°08 | Peroxide of iron.........scceecseeess 0-28 
STEN Casali a cp we anv. wehavnoaersdea decay 8:38 | Calcareous or bituminous matter. 3:08 
Magnesia...sccsccssssersecsseeseee 1°77 | Moisture and loss....cscsessesseeeee 1°41 
Abaca ie daaksl ksawssaddsenegsahk 1:40 100-000 
The specific gravity of this ore is 3°0553, colour close brown. The ore con- 
tains an intermixture of imbedded bivalve shells, 
