Vízügyi Közlemények, 1935 (17. évfolyam)

Kivonatok, mellékletek - Kivonat a 3. számhoz

36 ferent parts of the field varied between 700 and 4200 kg per hectare. Assuming careful work and mean growth conditions, an average yield of 2400—2800 kg per ha may be expected. It should be stated that in this district the average yield in wheat is 1200 kg per ha, and the price of rice is higher by 20—30 per cent than that of wheat. X. SHORT ARTICLES. New Contrivance for Measuring Low Velocities in the Water Experimental Station at Vicksburg. (U. S. A.) By DR. J. EIN WÄCHTER. Bentzel's instrument (see figure on page 528) is similar to the Pitot tube. When the air is excluded from the tube, the water flows through it with nearly the velocity which is to be measured. In the descending tube there is placed a coloured glass ball filled with air, which the updrive tends to move upwards, while at the same time the water flowing through the tube brings it downwards. The small ball takes a position of equilibrium according to the prevailing velocity, and the value of this velocity can be read on a scale prepared according to experience. XI. TECHNICAL LITERATURE. The following books are reviewed : Th. Rehbock : The Construction of the Apron of Overflow Dams and Spillways. First Congress of High Dams. (In German : Stockholm, 1933). Dr. Ing. О. Jüngling : Shutter Dams Employed to Bottom Outlets with Special View to Undermining. (In German : R. Oldenburg, München, 1934). G. Schonopp : Spray Irrigation and its Operation in Farming. (In German : P. Paray, Berlin, 1929). Dr. Ing. H. Schwartzmann : Downflow and Pressure Conditions at Shutter Dams. (In German : R. Oldenburg, München, 1934).