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Page:Popular Science Monthly Volume 41.djvu/782

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THE POPULAR SCIENCE MONTHLY.

that the absorption of immigrants has not been equal. The facts in this respect can not be given for 1890, but for 1880 they indicate what may be expected when the full facts for 1890 are reported. In 1880 the whole number of people engaged in agriculture was 7,670,493. Of this number 812,829 persons were of foreign birth; that is to say, 10·06 per cent of the whole number employed in agriculture in 1880 were foreign-born. The total number employed in manufacturing, mechanical, and mining industries in the United States in 1880 was 3,837,112. Of this number 1,225,787 were of foreign birth, and this number is 32 per cent of the whole number of persons engaged in these industries. The tendency, therefore, of our immigrants is to assimilate with our mechanical industries. This increases the supply of labor in comparison to the demand, and may in some localities tend to lower wages, and sometimes to cripple the consuming power of the whole body of the people. In 1880 12·52 per cent of the whole number of foreign-born persons were engaged in agriculture, while 18·88 per cent of the foreign-born were engaged in manufactures.

 

MUD AS A BUILDING MATERIAL.
By WILLIAM SIMPSON, R. I, M. R. A. S.

IT is necessary to premise that under the term "mud" I include sun-dried bricks. When bricks have been burned in the fire, the material becomes entirely changed and ceases to be mud, so I exclude them from consideration in the present paper as a building material. Wet earth made into blocks and dried in the sun differs in no way from a layer of the same laid on a wall.[1] Both methods were used in the East, and often combined in the same building. The reason for this is soon found out if you attempt to raise a mud wall. A layer of two or three feet thick must be allowed to dry and consolidate before another is placed on it, because the weight above would press out the soft material below, and the whole would tumble down. In some localities a layer of mud is put down at the commencement, and while that is drying bricks are made to be placed above.

It was during the cold season of 1884-'85, in traveling through Persia at the time of the Afghan Boundary Commission, that the


  1. Bricks of this kind, "when placed one upon another after being imperfectly dried, combined, under the influence of the weather and their own weight, into one homogeneous mass, so that the separate courses became undistinguishable. This latter fact has been frequently noticed in Assyria, by those who had to cut through the thickness of walls in the process of excavation." Perrot and Chipiez, A History of Art in Ancient Egypt, vol. i, p. 113.