298 Ilie Philosophical Society of Glasgoiv. 



MusHET Blackband Ironstone. — At 103 Fathoms — Average 

 Thickness 1 6 Inches. — This celebrated seam of ironstone was first dis- 

 covered about the beginning of this century by the late David Mushet, 

 who was then manager of the Calder Iron-works. The great value of 

 this stone consists not merely in its freedom from deleterious im- 

 purities, but in the large quantity of carbonaceous matter which it 

 contains, whereby it is capable of being calcined without the assist- 

 ance of an additional mixture of coal, as in the case of Clayband 

 ironstone. In its raw state it contains about 25 per cent, of iron, 

 and in its calcined state about 70 per cent. It was but partially 

 worked and used at the Calder Iron-works, and afterwards at the 

 Clyde Iron-works for a number of years after its discovery, as it 

 was considered too rich to be safely used in the blast furnaces, except 

 in a small proportion along with Clay ironstone ; but by experience it 

 was found that the furnaces worked well with large proportions of it ; 

 and about the year 1S25 it was used alone in the furnaces, without any 

 mixture and with complete success, and its superior quality in every 

 respect proved and estabhshed. About that time its value attracted 

 the notice of Messrs. Baird and others ; hence arose, in a few years, 

 first the Gartsherrie works, then the Dundyvan, Summerlee, Carnbroe, 

 Langloan and other works. These works drew their chief supply from 

 this seam for many years ; but, from its gradual exhaustion, other seams 

 have been explored, and resorted to during the last ten or twelve 

 years. This seam was therefore the foundation of the great increase 

 and prosperity of the iron trade in Scotland, especially when taken in 

 connection with the use of hot blast in smelting, which was discovered 

 and introduced by Mr. Neilson about the year 1829. The discovery 

 of hot blast so improved the smelting process, that raw coal could be 

 used in the furnaces instead of coke, and an immense saving was there- 

 by effected. With Blackband ii'onstone and Monkland Splint coal, and 

 hot blast, iron could be produced in this district cheaper than any- 

 where else in the world ; hence the important position it holds in that 

 trade. 



This valuable ironstone is now nearly all worked out, and may be 

 said to have ceased for some time past to contribute much to the 

 supply of the iron-works of the district, of which it was so long the 

 main stay and support. It never was found workable over more than 

 a small area, bounded on the north by a line drawn from Gartsherrie 

 to Drumshangy and Brownrig, near Airdrie, — on the east, by a line 

 drawn from Brownrig and Ardento Monkland and Newarthill, — on the 

 south, by a line drawn through Cleland, — and on the west, by a line 

 drawn through Woodhall, Rosehall, and Coatbridge. What remahis 



