58 REPORT—1840. 
CHEMISTRY. 
On the most important Chemical Manufactures carried on in Glasgow 
and the Neighbourhood. By Professor Tuomas TuHomson, of 
Glasgow, F.R.S. 
“ Glasgow being the seat of a great many interesting and important 
chemical manufactures, it occurred to me (said Professor Thomson) 
that it might be of advantage to those members of the Chemical 
Section, who have come from a distance, to give a short catalogue of 
the most important of these manufactures, that they might know what 
the information is which they may expect, and where they are to look 
for it.” 
1. Lron.—The smelting of iron has been practised in the neighbour- 
hood of Glasgow for more than fifty years. When the late Mr. Dun- 
lop, of the Clyde Iron Works, first became proprietor of those works, 
perhaps the only one then in the neighbourhood, the produce was only 
fourteen tons a-week, or 728 tons a-year. At present the quantity of 
iron smelted in Glasgow and the neighbourhood cannot be much less 
than 200,000 tons, which approaches to a fifth part of the whole iron 
smelted in Great Britain. The ore from which the iron is smelted is 
the carbonate of iron, or clay iron-stone, as it is usually called by 
mineralogists. This ore is very abundant all round Glasgow, and 
especially in the neighbourhood of Airdrie, where the principal works 
are now situated. Fortunately for the smelters, the iron-stone and 
coal-beds are associated together, the iron-stone either occurring in 
nodules or beds along with the coal. The rapid increase of iron smelt- 
ing has been the consequence of a discovery of Mr. Nielson, manager of 
the gas-works. This is now universally known under the name of the hot 
blast. The air is heated to more than 607° before it enters the furnace, 
by passing through a range of heated pipes. Under this treatment, it 
is found that the coals may be used without previous coking ; and that 
instead of seven tons of coal for every ton of cast iron, three tons, or 
even two and a half tons will suffice. There is also a diminution in 
the quantity of limestone necessary, and the produce of iron per week 
from the same furnace is considerably increased. It is said, that 
neither in Staffordshire nor in Wales is the hot blast attended with 
the same saving of fuel. Till of late years, no bar iron was made in 
Scotland, the smelters confining themselves to cast iron. About three 
years ago, Mr. Dixon commenced the manufacture of bar iron near 
St. Rollox, but, after some time, he abandoned the manufactory. It 
is now conducted on a great scale, by Mr. Wilson, at Dundyvon, and 
by Mr. Dixon, at Glasgow, and perhaps by other iron-masters. The 
heat raised in the puddling furnace is much greater than it was in 
Staffordshire, when Dr. Thomson witnessed the process there about 
twenty-five years ago. There is an interesting manufactory of steel at 
Holytown, not far from Airdrie, where the smelting and casting of steel 
may be seen : the heat necessary for this process is greater than for any 
