CURIOUS HYDRAULIC EXPERIMENTS.

New Zealand Times, Volume XXXIII, Issue 5360, 1 June 1878, Page 1 (Supplement)

CURIOUS HYDRAULIC EXPERIMENTS.

(From the Scientific American.)

A disagreement recently occurred In Germany between the Government and a number of; manufacturers relative to the classification of certain water-courses used by the latter for power purposes. Among other questions was one which involved the determination of the source of the waters of tbe Aacb, the settlement of which was important as affecting the interests of the manufacturers, and also from a purely scientific point of view. A French hydrographic engineer was charged with the work, and iu his report is detailed the curious way in which the problem was solved. The Danube River, proceeding from the Black Forest, flows 1 nearly directly from west to east, while tho waters of the Rhine move iu parallel direction, but inversely, from Lake Constance to Bille. The altitude of the two streams differs, the relative difference being about 800 ft., and the Danube iu the region referred to being some 2000 ft. above tbe sea, level; the distance separating the rivers being about 18 miles. The River Aaoh is a tributary of Lake Constance, and rises near the village of the same name at a point Similes from the Danube, and at, an elevation some 500 ft, lower than the level of the latter. The spring from which the Aaoh flows ’is one of the largest in Europe,'and its yield is about 1350 gallons per second. The Danube flows over a calcareous bed, tbe inclination of which is exactly the same as that of the ground from the Danube to the source of the Aacb. The calcareous soil ceases beyond the above-named source, and the bed of the river enters the alluvial earth which surrounds Lake Constance. The limestone of the Danube Valley is composed of irregular layers diversely inclined, very friable, stratified, split and divided. The soil is so peimeable that it absorbs the greater mimber of the springs and streams which rise between the Aach aud the Danube. For many years it has been noticed that tile Danube loses a portion of its water in this region, and that during dry seasons even the greater part of its flow disappears in crevices or veritable holes in its bed. -; The owners of factories situated on the Danube, in order to retain their water supply, stopped up these leaks, but in doing so they were at once opposed by the manufacturers whose wprks were located on the Aaoh, the latter claiming that the water lost by the Danube fed the Aacb, and to check the waste from one river to the other was to interfere with their just enjoyment of the smaller stream. The ques-. tion, however, was to prove that the assertion of the Aaoh manufacturers was a true one, namely,, does the.,water,from the Danube, by some subterranean infiltration, supply the Aacb, located, 1 as, already stated, nine miles' away? The first plan 1 suggested was to make the Danube water salt. This was proposed by Professor Knop, of Karlsruhe,; and accordingly 22,0001 b. of salt were placed in a hole iu the bed of the great river. ; ; Then water from the source of the Aach, was obtained every hour for several . days, and this. on,,being analysed' revealed the presence of the salt. In order to get still 1 better proof, M. Ten Brink decided. to take advantage of the wonderful , coloring .power ; of ; fluorescine. This substance is the phtaline of the resorcine obtained by treating at 374 deg. Fab. a mixture of pbtalic acid and. resorcine. Its formula is C2O H12'05, according to the equation of its formation C 8 H 4 06 (pbtalic, aoid) + 2(C6 H 6 02) (resorcine) =O2O Hl2 05 (fluorescine). 1 1 It is the first bf a'aeries of superb coloring , matters, according as there is introduced into its constitution bromine, iodine, chlorine, • and its . coloring power is so great that one part of fluorescine in:20,000,000 parts of water is quite sufficient to be recognised. On the 9th of October .last, at five o’clock in the afternoon;" 15 gallons of a solution of fluorescine were thrown into one of the orifices iu the-bed-of the; Danube.; On October 12,; the- observers stationed at the source of < tbe Aach observed the coloration of the water. It had, therefore, taken. about sixty hours for,: the colored ■ water to; traverse ; the soil and reappear. It is stated that tho Aaoh as it gushed from its springs presented a maguifi-,, cent intense green, which in the sun exhibited moie or less fluorescent reflections ranging from light green to brilliant yellow. The intensity of tho dye augmented from morniug uutii evening of October 12. Its effects were quite visible uutii about' 3 p.m. on the. 13th, when it gradually disappeared; Tho experiment was certainly a most remarkable one. Its repetition in other localities may prove of great value in the study of subterranean watercourses, while it offers a new method of geological investigation, worthy of general attention. ’•