Fejér László – Lászlóffy Woldemár: A hidrometria magyarországi fejlődése (1700-1945) (Vízügyi Történeti Füzetek 13. Budapest, 1986)
Idegen nyelvű összefoglalók
Ignác HORVÁTH Photography by ELLINGER from 1881. 15. D rawing by Ignác HORVÁTH on the circuit scheme of his signal recording device. 16. Photograph of Ignác HORVÁTH's device used for signalling and recording in flow velocity measurements. At right a Patek Philippe-made electric clock, in the middle a Mayer—Wolf-type four-arm chronograph (writing machine) with a motor moving the paper tape. In between, a relay is placed while behind it a Maidinger-type chromium acid open battery, used as electrical source, can be seen. At left stands one of the six batteries operating the chronograph, the other ones have been omitted to make the picture more perspicuous. 1 7. Hydrometrie station of Ignác HORVÁTH. Beside the small stairway a Pitot—Darcy tube can be seen. After use the sidewalk furnished with Mardrail could be withdrawn. This sidewalk was used when velocity measurements were performed in case of depths less than 2 m. The recording devices were located in an observation cabin. From the top of this cabin the pole of the wind gauge rose up high. The rod furnished with a flag was to assist alignment into a cross-section and a telemetric telescope was also mounted on it. At right a covered shelter was assured for workers. 18. Fixation of current meters and the equipment of lowering the instruments. An arm g projects from a horizontal beam consisting of two iron tubes filled with lead; on this beam fixed are, on the one hand, a vertical rod bearing three current meters (a 1 , a 2 , a 3 ) and, on the other hand, two bridles with logs Lj and L 2 . The operating direction of winches on platform D supported by columns N was contrasting in order to assure horizontal position for the beam while lowering. On the suspension chains marks were applied in one-metre spacing. The lateral swing of the holding rod was slowed down by rudder F. At left the pole of flag (M) assisting the alignment into a cross-section can be seen. 19. Situation plan of the Danubian stretch at the capital, indicating the site of flood measurements performed by Ignác HORVÁTH in 1876, and the cross-section surveyed at Thonet-yard, also showing the measurement verticals. 20. Steamer „Hungária" tows the measuring vessel upstream to ship „Harta" anchored in a line assigned upstream of the cross-section of measurement. The accurate alignment of the measuring vessel into the cross-section was managed by manoeuvring it downstream. Assistance of „Harta" was needed during the culmination of the flood wave only. Later she was replaced by a larger barge. Mihály DOLECSKO 21. Photograph of that Ertel-made Woltman-type current meter which was used in 1880 by Mihály DOLECSKO for his measurements in the Mosoni Danube-branch. The same type was used by H. GREBENAU, too, in his famous measurements on the Rhine. Jenő KVASSAY 22. Arrangement of the measurement performed by using floats at Tiszapalkonya. The floats were thrown into water successively along the anchoring line and when they reached the cross-section AA'their position were fixed on a surveyor's table located in the extension of crosssection CC, and time measurement was also started. When a float reached cross-section BB' the clock was stopped and on the surveyor's table the ray defined by the float and the fix of the section line was drawn again. Then the next float was thrown into the water along the anchoring line, but some 30 m farther from the point used previously and the procedure was the same as in the former case. For sake of higher accuracy, at each point of the anchoring line used for starting floats not only one but successively 5 to 6 floats were started and the mean of their velocities was accepted as surface velocity pertaining to the river zone concerned.
