Report on the Geological Survey of Connecticut. 159 — 
- “*During the first six months of the year 1833, when all these 
changes had been fully brought into operation, one ton of cast-iron 
was made by means of 2 tons 5} cwt. of coal, which had not pre=" 
viously to be converted into coke. Adding to this 8 cwt. of coal 
for heating, we have 2 tons 13} ewt. of coal required to make a ton 
of iron; whereas in 1829, when the cold blast was in operation, 8 
tons 14 cwt. of coal had to be used. This being almost exactly 
three times as much, we have from the change of the cold blast to 
the hot, combined with the use of coal instead of coke, three times 
as much iron made from any given weight of splint coal. 
**¢ During the three successive periods that have been specified, 
the same blowing apparatus was in use ; and not the least remark- 
able effect of Mr..Neiuson’s invention has been the increased effi- 
cacy of a given quantity of air in the production of iron. The 
furnaces of Clyde iron-works, which were at first three, have been 
increased to four, and the blast machinery being still the same, the 
following were the successive weekly products of iron during the 
periods already named, and the successive weekly consumpt of fuel 
put in the furnace, apart from what was used in heating the blast :— 
Tons. Tons. Tons, 
In ise’ from 3 eam 111. irda, rhe 403 Coke, pe 888 bem 
183 = Z 376 i 
BOOS; Md Sot ie “ “ 
“ < Comparing the sialaie of 1829 with the product of 1833, it 
will be observed that the blast, in consequence of being heated, has 
reduced more than double the quantity of iron. The fuel consumed 
in these two periods, we cannot compare ; since in the former, coke 
was burned, and in the latter, coal. But on comparing the consumpt 
of coke in the years 1829 and 1830, we find that although the pro- 
duct of iron in the latter period was increased, yet the consumpt of 
coke was rather diminished. Hence the increased efficacy of the 
blast appears to be not greater than was to be expected, from the 
diminished fuel that had become necessary to smelt a given quantity 
of iron. On the whole then, the application of the hot blast has 
caused the same fuel to reduce three times as much iron as before, 
and the same blast twice as much as before. The proportion of 
the flux required to reduce a given weight of the ore has also 
been diminished.’ 
“¢In Scotland, Mr. Nerson’s invention has been extensively 
applied to the making of cast-iron, insomuch that there is only one 
Scotch iron-work where the invention is not in use; and in that 
