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part 1 .] Hughes — Medlieott: Trials of Eaniganj Fire-bricks. 
the Bengal Iron Company’s proposed work, and others, who agreed in the favorable estimate 
formed of the quality of these bricks. 
The experiments ware, with the kind permission of Colonel H. Hyde, E. e,, Master of the 
Mint, conducted at the Mint furnaces. 
Mr. Hughes, who conducted the first trials, reported— 
1. “ The fire-bricks tested by me were furnished by the firm of Messrs. Burn and 
Company, and are stated to have been made from fire-clay obtainable in the neighbourhood 
of Mallapur.’ 
“ The results of my experiments are— 
“ lrf.—That the material from which they are made is very refractory, and capable of 
resisting high temperatures without sensibly fusing. 
“2nd .—That the bricks, however, have failed to sustain the high character for excellence 
which Mr. Cowhan (the Manager of the Kaniganj Pottery Works) has attributed to them, 
inasmuch as they shrink on being subjected to strong firing, and show a tendency to fissure. 
“ 3rd .—That compared with Glenboig fire-bricks they are inferior; but compared with 
Stourbridge fire-bricks they are somewhat superior. 
“ I attribute the shrinkage and Assuring to the texture being too fine; and this can only 
be remedied by the addition of a proper amount of burnt clay in coarse powder, or some 
infusible substance like silica. The particles of silica (quartz) must not be too fine, otherwise 
they may enter into combination with the clay. 
“ The usual proportion of raw to burnt clay is | of the former to -§ of the latter, 
and I believe this proportion was adopted in the manufacture of the fire-bricks from Rani- 
ganj. It does not appear to have answered however; but this was probably due to the burnt 
clay having been ground up too fine. On a purely practical point of this kind, I do not like 
to give a decided opinion, as experience alone can determine what the proper proportions 
ought to be, and I would suggest that separate sample bricks be prepared, containing varying 
proportions of ground brick and silica, and the particles to be of varying sizes. A series 
of experiments carefully conducted will, I feel sure, enable fire-bricks to be made that will 
possess all the qualities requisite for the special purposes to which they may be applied.” 
12 th September 1874. 
Details of experiments. 
(A) .—The brick marked A was subjected to a temperature of over 3,000 Fakrt. in a 
wind furnace, the fuel being English coke. It was purposely broken in half. 
Remarks. —The edges have stood well. 
(B) .—Was heated in the same furnace as a Glenboig brick, at a temperature considerably 
higher than the smelting point of cast-iron. 
Remarks. —It cracked, and was fissured throughout. 
(C) .—Was submitted to conditions similar to (B). 
Remarks. —It is superior to (B), but it is internally fissured. It contains 
an excess of alkaline earth, which has vitrified. 
(D) .—Was inserted in a plumbago crucible to avoid contact with the coke. This was 
carefully weighed and measured previous to insertion and after extraction 
Its tenderness was also noted. 
