21 8 SECRETS OF EARTH AND SEA 



of sea-coal in London, did not become important until 



the seventeenth century. It came very gradually > into 



use, and we find that Evelyn (the diarist) in 1661 noted 



the withering and bad condition of rose-bushes and other 



plants in London gardens, which be attributed to the 



pestilential action of the smoke given off by the newly 



introduced " sea-coal " which was increasingly used as 



fuel in London houses. The sea-coal was not yet largely, 



if at all, used in the production of iron ; and Evelyn as a 



forest-owner and lover of trees, has much to say about the 



necessity for attention to the cultivation of our forests in 



connection with the iron industry which then flourished 



in the Weald of Sussex ; charcoal procured by the slow 



burning or roasting of wood being the fuel used in the 



smelting furnaces, whilst the ore was the orange-brown 



wealden sand. It was during the eighteenth century 



that what we now call simply " coal " came rapidly into 



use — not only for domestic heating, but for furnaces of 



all kinds employed in industrial enterprise, and, at a 



later date, for the earlier and later forms of steam-engines. 



The smoke of the new coal was everywhere regarded as 



a terrible nuisance, and a source of injury to both animal 



and vegetable life. The poisonous action of coal-smoke 



is not due to the finely divided black particles of carbon 



of which it largely consists, but to the sulphuric acid 



derived from the small quantities of sulphur present in 



coal. It is calculated that more than sixteen million tons 



of coal are annually used in London alone for heating 



purposes, and that 480,000 tons of black carbon powder 



are discharged over London by its chimneys every year, 



together with very nearly the same weight of poisonous 



sulphuric acid ! 



What, then, is this " sea-coal " or " coal " of our modern 

 life ? We all know its black, glistening appearance, and 

 more or less friable character. Its nature and origin are 



