The brands, which are in raised letters on the pig, serve as a guide to the quality and place of manufacture. The brands are sometimes the initials of the manufacturer, but more commonly refer to the place of production. Thus the brands Blaenavon, Gartsherrie, Weardale, indicate at once to the initiated that the first is a Welsh, the second a Scotch, and the third a North of England pig-iron.
G.M.B. are letters often quoted in price-lists, etc.; they do not refer to any particular locality, but stand for "Good Marketable Brands."
As already stated, the engineer has but little personal concern with the peculiarities and shades of difference between the brands of the same or different districts. It is sufficient for him to specify that the finished iron he requires must stand certain tests, and the selection of ores, pig-iron, and other raw material, required to effect this is better left to the manufacturers.
There are several ordinary descriptions. The best works, such as Lowmoor, Bowling, Farnley, etc., use the local ores mixed with other kinds.
Scotch Brands, such as Colder, Clyde, Govan, Carribroe, Carron, Gartsherrie, Langloan, Coltness. This pig-iron, chiefly from clay ironstone, and used largely for foundry purposes; sometimes mixed with N. England pig-iron to improve its strength.
North of England Brands, such as Acklam, Ridsdale, Southbank, Weardale, etc., are chiefly from ores of the Carboniferous system, tougher and stronger than Scotch, and used chiefly for forge purposes. Cleveland Iron is from ore of the Lias formation.
Welsh Brands, such as Blaenavon, Gadlys, Tstalyfera, Pentyrch, are from good but lean ores, generally mixed with Spanish, Cumberland, or other haematite ores, and used in the district for rails.
Blaenavon is a cold-blast pig used for engine cylinders and other special purposes.
Haematite Pig-Iron - Askam, Barrow, Workington, Cleator, Carnforth, Harrington - is made from the rich ores of Cumberland. Is used largely by steel, tin-plate, and sheet-iron manufacturers. A special quality - "Bessemer Pig " (see p. 263) - is made for the Bessemer steel workers.
Northamptonshire Pig-Iron is made from poor ore, but useful to mix with others.
Shropshire Brands are Lilleshall, Madeley Wood, Old Park, etc.
Staffordshire Pig-Iron differs very much in quality, and is mostly used in the district. Much of the Staffordshire iron is made from ores from other counties.
Wrought Iron Brands.
In order to understand the different qualities of British wrought iron in the market, the relative cost of the different forms, and to form some idea of the brands by which they are distinguished, it will be well to examine the current Price List given at page 290.
It will be seen from that list that the prices of iron vary according to the shapes in which it is manufactured, according to the locality it comes from, and also with its quality, i.e. best, best best, or treble best.
Before proceeding further it should be mentioned that all good iron has some sort of mark upon it to indicate where it came from, although it does not follow that all marked iron is good; an unmarked iron may be suspected to be bad; the maker is probably ashamed of it.
In most cases the only sure way of ascertaining the quality of a piece of iron is to test it as described at p. 276; but as some engineers still specify certain brands in order to secure a good quality of iron, it will be as well to know what some of those brands mean.
It may be stated with regard to brands generally, that, though they differ in detail, they frequently consist of the maker's initials, name, or device stamped upon the bar or plate near its end, immediately after which is stamped either best, best best, or best best best, to indicate the quality; the letters B, BB, or BBB are often used instead of the words. The crown which is introduced in many brands has no special signification; indeed, several crowns have been known on very bad iron.
Some large exporters use their own marks for particular markets. Thus Messrs. Boiling and Lowe sell certain irons branded Bird with a horseshoe, crown, or similar, device, or with stars so placed that they can always trace the works whence the iron came.