IRON AND LIMESTONE. 181 



of ironstone and coal in the same formation in the same 

 mine, we may say renders these clay-hands and hlack-hands 

 of peculiar importance. Ahout 5,000,000 tons of pig or 

 cast iron are annually manufactured in Britain, and of this 

 the greater proportion is obtained from our coal-fields. 

 Looking at the peculiar phases of modern civilisation, it is 

 impossible to over-estimate the importance of an abundant 

 supply of iron. Indeed, without this abundance, our varied 

 machinery, our steam-engines, our railroads, gas and water 

 pipes, suspension bridges, iron ships, and other similar in- 

 ventions, would have been impossible, or if possible, would 

 have been on a limited and insignificant scale in comparison. 

 This work and application of iron is one of the leading 

 features of our times its malleability, strength, durability, 

 and cheapness fitting it for almost every purpose, from the 

 homeliest utensil of domestic use to the most elegant and 

 complicated machinery, and from the tiniest implement of 

 art to the most gigantic instrument of war. Ours is in 

 truth the Age of Iron, there being no industrial operation 

 in which that metal does not play an important part, no 

 enduring subjugation of the forces of nature unless through 

 its instrumentality and power. 



Besides coal and iron, LIMESTONE also takes rank as one 

 of the abundant and valuable products of our coal-fields. 

 Associated with coal and ironstone, it becomes of especial 

 value as a flux for the reduction of the latter in the blast- 

 furnace, and all the more valuable that it is obtained from 

 the same formation, and generally in convenient proximity. 

 It is also extensively used for mortar and cements, in agri- 

 culture, in tanning, bleaching, and other industrial processes, 

 and not unfrequently some varieties are hard enough and 

 beautiful enough in texture to be raised and polished as 

 marbles. Taken together, there are no mineral substances 

 so valuable as coal, ironstone, and limestone ; and it seems 



