Page:Popular Science Monthly Volume 51.djvu/439

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FRAGMENTS OF SCIENCE.
427

gree, and it bears these features through the entire course to the Gulf. The large tributaries farther south modify but can not control their overwhelming influence. The two periods of flood characteristic of each of these large tributaries have an important bearing upon the continuance of high water in the main river, pouring their floods in one after the other as the force of the preceding flood is beginning to be spent, so that the tendency is for the main river to flow in strong volume until well into the summer. The river is a result; its tributaries are the cause. Viewed broadly, a general similarity of behavior is observed; yet each feeder of the main river has its special cycle of alternations between high and low water; each great line of drainage has its special feature of flow. Were the secondary watercourses followed, the vast Mississippi water shed would be seen covered by countless brooks and rivulets, each affected by local conditions, yet all obeying a few fundamental laws, "which gather the waters as in the hollow of the hand and pour them through a single channel to the sea."

The Turbinia.—In a recent issue of Industries and Iron is a detailed description of the Turbinia, the vessel which recently attained the highest velocity ever reached by a steam vessel, an average of 323/4 knots on the measured mile. As her name suggests, she is fitted with steam turbines instead of the ordinary form of engine. The Turbinia was built by a syndicate formed especially for the purpose of testing the application of the compound steam turbine to marine propulsion. She is 100 feet in length, 9 feet beam, and 441/2 tons displacement. The original turbine fitted in her was designed to develop upward of 1,500 actual horse power at a speed of 2,500 revolutions per minute. The boiler is of the water-tube type, for 225 pounds per square inch working pressure. The hull is built of steel plates, varying in thickness from 1/16 to 3/16 of an inch. A curious difficulty was encountered in the early trials. It was noticed that a great deal of power was being lost somewhere, and it finally turned out that, owing to the high speed of the propeller, what is known as cavitation was produced—that is, the screw tended to scoop out a hole in the water and run in this, thus using up a part of the energy simply in maintaining this cavity. This difficulty has been, to some extent, overcome by altering the pitch of the blades, but it Is believed that further experimentation will result in overcoming this fault more completely, and hence make a still higher rate of speed possible.

German Colonies for Unemployed Workmen.—The first of the German Arbeiter Kolonie, or refuges for workmen out of employment, one of which has been described in the Atlantic Monthly by Mr. Josiah Flynt, was established by Pastor von Bodelschwingh at Bielefeld, Westphalia, about 1882. There are now twenty-seven such colonies in Germany, where men able and willing to work may go, and at least pay their way till some more profitable labor is found. Connected with them is an estate near Berlin, where men who have proved deserving may acquire a piece of land and eventually set up homes of their own. Applicants for help must promise to stay in the colony at least four weeks, and have the privilege of staying longer if no work has been found for them outside; while the managers are on the lookout for work for them, in order that they may go and other out-of-works may take their place. The colonies are supported by contributions and the proceeds of the work of the colonists. Mr. Flynt applied at the Berlin colony at Tegel, and, on complying with the conditions required, was assigned to a section and set to making straw cases for wine bottles. He was expected to work to the best of his ability and to show respect to the officials—a Hausvater and a foreman, the only outsiders connected with the institution. The day was spent according to a prescribed routine, beginning at five o'clock in the morning and ending at nine o'clock at night, while Sunday was given to church and rest. Every man received a mark, or twenty-five cents, a day, and some, working by the piece or at special work, made a mark and a half. Out of these earnings, eighteen cents a day were taken for food and lodging. Several men had credit in the colony treasury. The food was simple but abundant, and the beds were fairly comfortable. A store was opened on Saturday afternoons, where the colonists