Gas-works 82,500 85,000 93,000 100,000 102,150 107,950 112,000 Iron-works 4,000 5,000 5,300 6,000 5,050 6,300 12,000 Shale-works 18,000 21,000 22,000 23,000 24,750 26,600 28,000 Coke and carbonising works 2,000 2,700 2,500 3,000 2,300 2,800 5,000 CHAPTER XI. BONES _Early Use of Bones._ A most important manure, and one to the history of which very peculiar interest attaches, is Bones. Employed first in 1774, their use has steadily increased ever since, and their popularity as a phosphatic manure is among farmers in this country quite unrivalled. Like guano, although to a less extent, the early practice of using bones has done much to arouse interest in the problems of manuring, and to bring home to farmers the principles underlying that practice. It was from bones that Liebig first made superphosphate of lime, and the distinguished veteran experimenter, Sir John Bennet Lawes, has told us that the benefit accruing from the use of bones on the turnip crop first drew his attention to the interesting problem connected with the application of artificial manures. Bones were first used in Yorkshire. Shortly afterwards they were applied to exhausted pastures in Cheshire. Soon their use became so popular that the home supply was found inadequate; and they were imported from Germany and Northern Europe, Hull being the port of disembarkation. So largely were they used by English farmers, that Baron Liebig considered it necessary to raise a warning protest against their lavish application. "England is robbing all other countries of the condition of their fertility. Already, in her eagerness for bones, she has turned up the battle-fields of Leipzig, of Waterloo, and of the Crimea; already from the catacombs of Sicily she has carried away the skeletons of many successive generations. Annually she removes from the shores of other countries to her own the manurial equivalent of three millions and a half of men, whom she takes from us the means of supporting, and squanders down her sewers to the sea. Like a vampire, she hangs upon the neck of Europe--nay, of the entire world!--and sucks the heart-blood from nations without a thought of justice towards them, without a shadow of lasting advantage to herself."[216] _Different Forms in which Bones are used._