the Finnish proper and the Hungarian, possess a marked superiority to the others. Most of the languages of the family are known only in their present condition. None of the branches has ever had a properly national literature, if we except the mythic and legendary songs of the Finns and the mostly lyric popular songs of the Hungarians; but even some of the remoter tribes, under the influence and by the aid of foreign teachers, have acquired the art of writing, and have brought forth religious and historical works, while the Hungarian and Turkish have developed important literatures. It is also believed that on the cuneiform monuments of Mesopotamia and Persia is represented, in the inscriptions of the third order, a Ugrian dialect, now frequently designated as Accadian, and that we have there authentic evidence and remains of an ancient Ugrian civilization, which preceded and formed the basis for that of the other races in the same regions. F. Lenormant has recently (1874) written a grammar of the Accadian on this assumption of its value. These results of a small number of investigators are not yet fully accepted by scholars in general. See Rémusat, Recherches sur les langues tartares (Paris, 1820); Rask, in several of his philological works; Schott, in numerous memoirs published by the Berlin academy, especially Ueber das altaische oder finnisch-tartarische Sprachengeschlecht (1849); Castrén, in a series of grammars, essays, accounts of travel, &c. (St. Petersburg, 1853-'8); Max Müller, “Letter on the Turanian Languages,” in Bunsen's “Philosophy of Universal History,” vol. i., and “Lectures on the Science of Language” (London, 1861); and Pauly, Description ethnographique des peuples de la Russie (St. Petersburg, 1862).
TURBINE (Lat. turbo, a whirling, or that which whirls), a water wheel through which the water passes, guided by channels in the wheel itself, and usually by other passages exterior to the wheel which cause it to impinge on the wheel buckets at the proper angle to secure efficiency. The guide curves (as the walls of the last named channels are called) and the buckets of the wheels are usually both curved in such manner that the water shall enter the wheel as nearly as possible without shock, and shall leave it with the least possible velocity. Turbines are generally, but not always, set in the horizontal plane, their axes being vertical; their size diminishes as the height of fall increases, and for falls of ordinary height they are very much smaller than the ordinary forms of so-called “vertical” water wheels, an advantage which increases with the height of fall. Their smaller size gives necessarily a high velocity of rotation, which constitutes their most important advantage over the older forms of wheel; it permits the adoption of less heavy and expensive machinery for transmitting the power, dispenses with gearing, and gives greater regularity of speed and nearly equal efficiency under all heights of fall. The turbine was introduced into general use by Fourneyron in France in 1827, and soon after by Fairbairn in England and by Boyden in the United States. Turbines are classed as outward-flow, inward-flow, and parallel-flow wheels, according to the direction taken by the water in passing through them; but the principle already enunciated applies to all. Could the water be entered upon the wheel absolutely without shock, and discharged absolutely without velocity, the efficiency of the wheel would be perfect, and the energy of the fall would be all transformed into work. The efficiency of good turbines, under favorable circumstances, approaches 80 per cent., and has been known to exceed that figure; the usual value is about 75 per cent. The efficiency is determined as follows: The amount of water flowing through the wheel is ascertained by gauging; its weight, measured by the height of fall, indicates the maximum power of the stream, or the power available. The actual amount of power utilized by the wheel is determined by measurement with the dynamometer. If R = the resistance and v = the velocity with which the wheel overcomes that resistance, R × v = the work done in the unit of time, and Rv = WhC, in which expression W is the weight of water flowing per second, h the height of fall, and C the coefficient of efficiency, or that fraction of the total available fall which is actually utilized by the wheel; the value of C is the “modulus” of the wheel. This value is capable of being estimated with approximate accuracy by the designer of the wheel, and the performance thus predicted, by the use of formulas involving quantities dependent in magnitude upon the forms of the guiding channels. Turbines give the highest efficiency when their speed is between 0.5 and 0.7 of that due to the height of fall. The velocity of direct flow, or that with which the water passes through the wheel, is to be preserved as nearly uniform as possible, and the passages are to be given such form and magnitude of cross section as will insure that uniformity. The velocity of whirl is made as nearly as possible equal to the rotary velocity of the wheel, and the water is thus passed upon the wheel without shock. It should glide over the buckets without sudden change of velocity, and should finally pass out with a speed opposite in direction and equal in magnitude to that of the wheel, thus dropping out of the wheel with the least possible velocity of flow, and with its original vis viva transformed into mechanical energy. Fig. 1 is a vertical section exhibiting the construction of the Boyden outward-flow turbine, made by the Holyoke machine company. A is a quarter-turn leading the water smoothly upon the wheel; B is the lower curb; C the disk carrying the guides; D the wheel with its guide channels, shown with the guide curves more perfectly in the plan, fig. 2; E is a disk con-
