mechanical knowledge. The Romans, though they did not commonly use such large stones in their own constructions, carried off the largest obelisks from Egypt and erected them at Rome, where more are now to be found than remain in Egypt.
It has sometimes been questioned whether the Egyptians had a knowledge of steel. It seems unreasonable to deny them this knowledge. Iron was known at the earliest times of which we have any record. It is often mentioned in the Bible, and in Homer; it is shown in the early paintings on the walls of the tombs at Thebes; it has been found in quantity in the ruined palaces of Assyria; and in the inscriptions of that country fetters are spoken of as having been made of iron, which is also so mentioned in connection with other metals as to lead to the supposition that it was regarded as a base and common metal. The quality of iron which is now made by the native races of Africa and India is that which is known as wrought-iron. Dr. Percy says the extraction of good malleable iron, directly from the ore, "requires a degree of skill very far inferior to that which is implied in the manufacture of bronze." The supply of iron in India as early as the fourth and fifth centuries seems to have been unlimited. In the temples of Orissa iron was used in large masses as beams or girders in roof-work in the thirteenth century, and India well repaid any advantage which she may have derived from the early civilized communities of the West if she were the first to supply them with iron and steel. If we look still farther to the East, China had probably knowledge of the use of metals as soon as India, and, moreover, had a boundless store of iron and coal. A great future is undoubtedly in store for that country; but can the race who now dwell there develop its resources, or must they await the aid of an Aryan race? The art of extracting metals from the ore was practised at a very early date in this country. The Romans worked iron extensively in the Weald of Kent, as we assume from the large heaps of slag containing Roman coins which still remain there. Coal, which was used for ordinary purposes in England as early as the ninth century, does not appear to have been largely used for iron-smelting until the eighteenth century, though a patent was granted for smelting iron with coal in the year 1611. The use of charcoal for that purpose was not given up until the beginning of this century, since which period an enormous increase in the mining and metallurgical industries has taken place; the quantity of coal raised in the United Kingdom in 1873 having amounted to 127,000,000 tons, and the quantity of pig-iron to upward of 6,500,000 tons.
The early building energy of the world was chiefly spent on the erection of tombs, temples, and palaces. While in Egypt, as we have seen, the art of building in stone had 5,000 years ago reached the greatest perfection, so in Mesopotamia the art of building with brick, the only available material in that country, was in an equally ad-
