Page:Popular Science Monthly Volume 33.djvu/588

572 all to be found in the Astor Library and the American Geographical Society's maps and atlases—that the root of the name America was widely scattered over Central and South America at the time of the conquest. It appears in the kingdom of Amarca, Caxamarca (or Peru), in Amaraca on the west coast of Central America, and in the forms Cundin Amarca (Bogota), Tamaraqua, Amaracapand, Caxamaraca, Andamaraca, Cataraarca, and many others, applied to various places, which are indicated on the maps with which the pamphlet is illustrated. As the authorities for these statements are fully described and easily accessible, students have ample opportunity for verifying or refuting Mr. St. Bris's theory. In further confirmation of these views, M. Marcou asserts that Vespucci's name was Alberico, or Albert, and never Amerigo, till he had returned from his American voyage and had adopted or been given a name commemerating his travels.

Changes on the Zambesi.—According to the observations of British Consul O'Neill, of Mozambique, the Zambesi River is working out important changes in its course near Maruru. About six miles south of the position of his camp was a long, swampy lake, which once formed the course of the river. Some obstruction in the bed of the stream deflected its course to the northward, and the old bed was left as a still lake or backwater, which is now filled only from its eastern extremity. This alteration has made great havoc on the northern bank of the river, where the rush of waters has torn and continues to tear away the country which separates the Zambesi from the Mutu and Barabango and other swampy depressions that drain into the Quaqua or Quillimane River. A little more than two years ago the African Lakes Company purchased a house at Maruru which stood eight hundred or one thousand yards from the river-bank. When Consul O'Neill visited the place in April, 1884, the river was running swiftly past the front walls of the house, the foundations of which it had already sapped. The front rooms had fallen in, and only the back part of the house was habitable. These changes are destined, of course, to make considerable changes in the delta of the Zambesi, and in the depth of channels now navigable. No improvement has taken place in the method of navigating the Zambesi, and no attempt has been made to improve it since it was first ridden upon more than three hundred years ago. Boats which will just do on a still-water canal, have to be forced against a powerful current, "at times with oars, at times with paddles, at times pulled along shore with the crew harnessed to a rope, not unfrequently swept into mid-stream by the strength of the current, and turned like a top."

The American System of Water-Purification.—As described by Prof. Albert R. Leeds, this comprises three distinct features: artificial aeration under pressure; precipitation of dirt, sewage, hardening constituents, and coloring matters by harmless precipitants; and mechanical filtration through filters capable of rapid reversal of current, and cleansing by mechanical means. Artificial aeration was first applied to a city water-supply, by Prof. Leeds, in Philadelphia, in consequence of an extremely offensive taste and odor developed in the Schuylkill water, in January and February, 1883.

This treatment has produced a marked improvement, as shown by analysis, in the quality of the water of a number of cities which have employed it, has corrected the offensive taste and odor, and has stopped the growth of green scum in reservoirs.

The reasons for advocating the use of air under pressure are, first, because the disagreeable taste and odor in unportable water are frequently due to gaseous and volatile impurities, which can be largely swept out of the water by the use of an excess of air acting mechanically as a deodorizer and disinfectant, thereby exerting a sweetening action in the manner of a water-scrubber; and, second, because chemical and biological analysis show that where sewage is being broken up it is in presence of large numbers of bacteria, which grow and multiply upon this material. Through the vital processes of these bacteria oxygen is rapidly absorbed and carried to the sewage, which is thereby broken up into nitrites, nitrates, carbon dioxide, and other partly or wholly oxidized compounds. After the work of these microbes is completed, they either perish or remain as resting spores, and then they should be removed, together