1854.] OF THE ROYAL INSTITUTION. 437 
hundred tons of materials, to supply the requisite heat for which, a 
powerful and constant blast of air is sent in at three or four different 
sides through tubes surrounded with a stream of cold water, and 
which are called “ Tuyeres.’’ Some of the large Welsh furnaces 
consume upwards of 20,000 gallons of air per minute, a quantity 
exceeding in weight the totals of all the solid materials used in 
smelting. The blast enters the furnace under a pressure of from 
two to three pounds and a half to the square inch, and (unless pre- 
viously heated) at a lower temperature than the external air, in 
consequence of its compression in the blowing machine, by which 
latent heat is separated and lost, which heat it again obtains at the 
expense of surrounding objects as it escapes in its recovered state 
of expansion from the Tuyere. It is almost the universal rule, how- 
ever, at the present time to heat the air to about 600° before it 
enters the furnace, by which an effective increase of about 1th or 
of 360° F is obtained. The influence which this capital improve- 
ment (first introduced about twenty-five years ago by Mr. Neilson 
at the Clyde Iron-works) has had on the iron manufacture has 
been immense. It has in many cases enabled manufacturers to in- 
crease their weekly production of iron 50 per cent., and to produce 
a better sort of cast-iron from inferior materials. It has effected 
a great saving of fuel; and it has enabled the Scotch Iron-masters 
to smelt alone and with coal the black band ironstone discovered 
by Mr. Mushet in 1801. 
The great importance of the hot blast, and the influence of an 
uniform temperature on the working of the furnace, is well shown by 
the following statement furnished by F. Levick, Esq. the intelligent 
Manager of the Cwm Celyn and Blaina Works. (The Lecturer 
took the occasion of mentioning this gentleman’s name, to express 
the obligations he was under to him for the facilities he had re- 
peatedly offered him for studying the details of the iron manufactnre 
at the above admirably conducted works, and for the specimens of 
the various interesting products which were on the table.) 
It is to be understood that both furnaces were making White 
or Forge Iron to be afterwards manufactured into Railway bars. 
No. 1. Furnace at Cwm Celyn ; —one week’s work, ending 
7th April, 1854. 
The blast was not sufficiently heated, the blast stoves being out 
of repair, and the furnace was ‘ scouring.” 
Charges driven, 652 ; Tron made, 181 tons 9 cwt. 
Consumption of fuel on the ton of Iron made. 
Cwt. Tons. Cwt., Cwt. 
Coal burthen 10 378 Charges = 189... 0 = 20°88 
Coke .,; 6 274 . . = 88.11 = 978— 
ee 
161 652 30°66 
