Page:Popular Science Monthly Volume 61.djvu/521

Rh and anthracite coal is now almost eight million tons, and, though this is small as compared with the home consumption, yet the export is likely to increase more rapidly, and a leading ironmaster in Germany predicts that in ten or fifteen years America will supply all the Mediterranean coast with coal and iron. He says that cheap production and transport will be the chief factors and will more than counterbalance the nearness of Britain. A few years ago Britain led as a coal producer, but now the United Kingdom is surpassed by the United States. In 1900 Britain produced two hundred and twenty-five million tons of coal, in 1901 she produced two hundred and nineteen million tons only. This difference of six million tons is almost exactly equal to the excess of exports over imports of coal in the United States.

An industry of very rapid growth in the United States is that of cement. There are two large and important classes of cements, called natural cement and Portland cement. In the United States natural cements are still produced in greatest amount, but the growth in output of Portland cement has been very rapid, and Portland cement bids fair soon to surpass natural cement in quantity. Not many years ago nearly all the Portland cement was brought from England, American Portland cement being considered inferior; but now by the introduction of rotary kilns and other improvements it is claimed that American Portland cement is made at least equal to and probably better than English cement.

The production of natural and Portland cement was in 1896, 9,510,355 barrels; in 1900 it was 20,486,274 barrels. This tremendous growth is due to the greatly extended use of cement in buildings and pavements and in structural works of many kinds in which stone was formerly used. This growth in consumption has not been accompanied by a growth in importation. On the contrary, the imports have declined to a slight extent, being in 1896 3,558,166 barrels, and in 1900 3,182,245 barrels. The export is small, but there is an increase from 87,910 barrels in 1896 to 186,586 barrels in 1900. This means that the cement factories have been able to keep up with the growth in the demand at home and have had a slight surplus.

The soda industry is one of the most important chemical industries, and in it England was for a long time supreme and America imported largely from her. Now, however, the importation is small, America providing her own soda to a great extent. In 1896 the soda imported was 86,991 tons, in 1900 it was 33,482. Common salt is the starting point for the manufacture of soda, and it is used for many other purposes as well. The world's consumption of salt has grown during the last twenty years, but Britain's output has fallen off. This appears to be largely due to American competition. In 1880 the United Kingdom produced nearly 2,700,000 tons of salt and the United States 800,000