1900 it rose to 8,482,000 barrels. In 1905 it reached the bewildering total of 35,246,000 barrels. With this advance in the use of cement, there must be a corresponding advance in the use of crushed stone. Hence the good luck of the people of Chicago in having a rock-heap on their hands at just this particular moment.

From the site of that rock-heap, Mr. Ewen will ship not only crushed stone but complete concrete blocks, in standard shapes and sizes, ready to be put together,

to building engineers, will be an age of concrete. Therefore cement is a growing proposition. And so is crushed stone.

A short time ago an eighteen-story skyscraper in Cincinnati was built entirely of concrete. It was not a steelcage building; it was a concrete building. The new method of steel construction was superseded by the newer method of concrete construction. That Cincinnati skyscraper, called the Ingalls Building, is the first big monument to the new concrete age. It is, from top to bottom, a monolith of artificial stone-a solid, tenacious mixture of crushed rock and

cement.

In 1880 the United States manufactured 42,000 barrels of cement. In 1890 this figure rose to 335,000 barrels. In

like so many bricks, to make factories and stables and freight-houses and residences.

But concrete does not make buildings alone. It also makes the conduits, with the little square tubes in them, that carry electric wires underground. It also makes everlasting bridges and viaducts. It also makes big retaining walls for canals and rivers. It also makes sewers and tunnels, usurping the place of brick. It also makes the 3,000 columns that support the Sears-Roebuck plant on the West Side of Chicago. It also makes fence-posts. It also makes telegraph poles. And, finally, it even makes railroad ties.

An eastern railroad was recently obliged to plant a forest in order to be sure that fifteen years from now it would have

rulers of that province will be interesting, not only in the history of concrete, but in the history of the politics of northern Illinois. Mr. McCormick and Mr. Ewen are almost as novel in politics as concrete is in railway roadbeds.

McCormick, an ornament of the "leisure class" and the polo field, entered the public service as an alderman immediately on his graduation from college, and has already climbed, in the face of the original distrust of him, to one of the most important offices in the gift of the citizens of Chicago. Ewen, an engineer of historic accomplishments in private service, went after the rock-heap contract on the simple basis of making the

ing the débris. Joliet saw the necessity for water communication between the Great Lakes and the Gulf. He also saw just where that communication could best be secured. He suggested a canal between the Chicago river and the Desplaines river. It would be, he said, an enormous commercial undertaking. It would be a mile and a-half long, and would have water enough in it to float canoes at all seasons of the year.

To-day Mr. Ewen must buy half a million dollars' worth of machinery before he can make a start at beginning to remove the mere waste product of that "water communication" that Joliet fore

saw.

S

half

BUBSTANTIAL progress is at last being made by the United States Government in the canalization of the Ohio river from Pittsburg to Cairo. A lock and dam at Fernbank, some fourteen miles downstream from Cincinnati, is about completed. This mechanical wonder, one of the engineering feats. of the age, will cost $1,050,000 when completed. Cincinnati will have at that point the finest permanent harbor of a nine-foot stage on the river, throughout the entire year; and the stream for a distance of fifty miles. above the dam will always be navigable, no matter

how low the water may happen to be elsewhere.

This pooling of the Ohio, which at present is never navigable for any distance for more than four months in the year, will be the accomplishment of what the Ohio River Improvement Association

lock through which all boats going up or down the river will have to pass. The lock will be 110 feet wide by 600 feet long. These dimensions, it is believed, will enable it to accommodate the largest tows that now float on the river. The inner guide-wall of the lock, running along the Ohio shore, will have an extreme length of 1,851 feet. Its chief purpose is to afford guidance for boats in entering and leaving the lock.

In seeking a suitable foundation for this wall, huge excavations have to be made in the river bank. Reaching out from this wall, will be the dam proper, extending to the Kentucky side of the river. At present, work is confined mostly to the Ohio shore. There is much to engage attention there, as it is on the grounds adjacent to the lock that all the buildings, power-houses, offices, storehouses, etc., will be located. There will be permanent residences for workingmen and the superintendents, the whole forming a sort of little government colony when once its members are gathered to gether.

With good weather and low water, the lock may be completed in 1908, but it is thought that the finishing touches will not be given until the year following.

The importance and national character of this work may be better understood when it is known that Pittsburg coal shipped down the Ohio last year was destined for Japan, to be used by the Mikado's fleet in its fight against Russia. Manufactured goods from the headwaters of the Ohio river find their way downstream in vast quantities, for foreign shipment. This river transportation from Pittsburg alone, in 1905, amounted to 3,302,139 tons. The stream, however, has never been navigable for more than four months in a year. In 1904, about 16,000,000 tons of freight was moved on the Ohio when freshets made transportation possible, about one-half being towed and the other carried by small boats. The cost per ton for towing coal to New Orleans from Pittsburg, was 675-1,000 of a mill per mile. This included the cost of the barges, or coal-boats, in which it was transported. Many of these craft are set adrift in the Gulf after reaching New Orleans, because it would not pay to bring them up the Mississippi river to the Ohio, where an unnavigable condition would cause delay of many months before the barges could again reach Pittsburg. With an improved river, this cost of transportation, it is estimated, will be re