Meanwhile, the world's production of wrought iron has not been stationary. I cannot give very accurate figures, as the statistics of some countries are incomplete, while in others the output of puddled bar only, and not that of finished iron, has been ascertained. The nearest estimate which I can arrive at is a production increased from about 5,000,000 tons in 1869 to somewhat over 8,000,000 tons of finished iron in 1882; an increase all the more remarkable when it is considered that at the present time iron rails have been almost entirely superseded by steel. It is due, no doubt, in part to the extensive use of iron plates and angles in shipbuilding; but, apart from these, and from bars for the manufacture of tin-plates, the consumption has increased for the numberless purposes to which it is applied in the world's economy.
There has been no striking improvement in the manufacture of puddled iron, partly on account of the impression that it is doomed to be superseded by steel. Mechanical puddling has made but little progress, and few of the attempts to economize fuel in the puddling furnace, by the use of gas or otherwise, have been successful. I would, however, draw attention to the remarkable success which has attended the use of the Bicheroux gas puddling and heating furnaces at the works of Ougrée, near Liege. The works produce 20,000 tons of puddled bars per annum, in fifteen double furnaces. The consumption of coal per ton of ordinary puddled bar is under 11 cwt., and per ton of "fer à fin grain" (puddled steel, etc.) 16 cwt. The gas is produced from slack, and the waste heat raises as much steam as that from an ordinary double furnace. The consumption of pig iron per ton of puddled bar was rather less than 21½ cwts. for the year 1882; and that of "mine" for fettling was 33 lb. The repairs are said to be considerably less than in the ordinary furnaces, and the puddlers earn from 25 to 30 per cent. more at the same tonnage rate.
I have already mentioned the large consumption, reckoned in tons of pig iron, of the materials for shipbuilding.