Page:Popular Science Monthly Volume 31.djvu/150

140 cold current is of least strength, as in August and September, the Gulf Stream comes within ten miles of Barnegat; at other times it is distant one hundred and twenty miles, changing with the amount of the cold current and of the wind. If we had not the cold wall between our shores and the Gulf Stream, it is fair to presume that we should have a less stormy coast, as the juxtaposition of these two currents with their difference in temperature must from that circumstance tend to an unstable condition of atmospheric equilibrium. Our cold northwest winds would then sweep to the north of us, and become westerly and southwesterly winds.

Production of Coke in the United States.—It is shown by the report of Mr. Joseph D. Weeks, of Pittsburg, to the United States Geological Survey, covering the period from 1880 to 1885, inclusive, that Pennsylvania stands first in the rank of coke-producing States, Alabama second, West Virginia third, and Tennessee fourth. The largest coke-producing locality in the country is the Connellsville region of Pennsylvania, in which were made 3,096,012 of the 5,106,696 tons, or 60·6 per cent of the coke produced in the United States in 1885. The second largest producing district is what is called the Irwin-Latrobe district, which lies along the Pennsylvania Railroad, from Larimer to Blairsville, and is, in part, the northerly extension of the Connellsville coking-field. The number of establishments has slightly decreased, but the number of ovens was increased from 1884 to 1885 by 2·8 per cent, and was in the latter year 20,116. While the production of 1885 increased over that of 1884, it was not as great as in 1883. There has been no increase in the value per ton of coke for three years.

How Harbor-Channels may be kept clear.—Professor Lewis M. Haupt addressed the Section of Mechanical Science and Engineering of the American Association on "River and Harbor Improvements, with Special Reference to the New York Entrance." He maintained that large and weighty structures intended to regulate currents, which rest or depend upon sandy or alluvial bottoms, violate the fundamental requirements that they shall not oppose the ingress of the tide or injuriously modify the currents. Dikes and jetties also are below the plane of action of waves of translation; while dependent upon their mass they are not entirely coherent; and they are wasteful, and result in serious modifications in the regimen of rivers and harbors. He suggested as a preferable system, one consisting of deflectors intended to be attached to buoys or floats, anchored to heavy moorings, and guyed in place on the ebb side by wire cables or chains. This system is composed of units or parts readily assembled, which occupy little space, yet control the currents, and deflect them upon the obstruction to be removed. By it the prism of water passing through a given section can be increased indefinitely, while the aperture of discharge may be diminished, thus producing any required velocity. Stress was laid upon the importance of applying a method which should be limited to the removal of so much of the crest of the bar as would secure the requisite channel, and no more.

The Amazons Valley.—Mr. James W. Wells, in an address before the Royal Geographical Society, on "The Physical Geography of Brazil," divides the rivers of that country into three great systems: the basin of the Amazons, including also the Tocantins and Araguaya; the basin of the Plate River, and the many distinct and separate rivers draining into the Atlantic. The Amazons basin is divided into the bottle-shaped, low-lying forest of the upper valley, 1,300 miles long by 800 miles broad, and its circumscribing elevated table-lands, which, near Obidos and Santarem, approach close to the banks of the main river, and constitute the neck of the bottle-shaped area. Throughout the length of this river, east and west of Obidos, the adjoining land is so low and flat that we have in many cases rather a series of more or less parallel streams than one great, clearly defined stream. It is possible to go in a canoe up the whole of the valley in these lateral channels, and also to pass through the deep forest by natural canals, from one tributary to another, without once entering the main river. It is a singular feature of the Amazons Valley, considering