CURIOUS HYDRAULIC EXPERIMENTS.

Nelson Evening Mail, Volume XIII, Issue 146, 18 June 1878, Page 4

CURIOUS HYDRAULIC EXPERIMENTS.

tFroni the j^Scientifio American."], 7;4 disagreement reoently Qccufereid in .^ermany between the Government jand » number of manufacturers relativja to ■ the . classification, of; certain : water- c courses used by the latter for power purposes. , Among other questions iwas one which, involved tbe*determina;iion j of the .sources of the Aach, the sehle-' inent of.which was important as affecting the interests of the manufacturers, and also from a scientific. point of view' A French hydrographic engineer-was charged with the work, and in his report is detailed the curious way '}_''• wbich the problem was solved. |The I Danube river, proceeding from the Black.Forest, flows nearly, directly from west to east, while the waters of the Bhine move in parallel direction, but inversely, from Lbke Constance to ' Bale. The altitude of the two streams ..differs, the relative difference teing about 800ft., and the Danube in the . region referred to being? some 2000ft above the sea level ; the distance sepa-A-r rating the rivers being about- 18 mileß. The river Aach is a tributary of Lake .Constance, and rises hear the village of *-„4Miißame,:name at a point nine miles from the Danube, and at an elevation some 500ft, lower than tbe level of: the iatteiv The spring from* -which ! the : Aach. flows> is oneof the in "« Europe, and its yield is about 1350 1 gillons per second. . Tjlie Danube flows o^er a calcreous bed, the inolinatio'n of : which is exactly the same as that of the ground from the Danube to the sojjrce of the Aach. The calcareous soil soil ceases beyond the above-named 'eOurce, and the bed of the river; enters the illovia^ earthj'which surrounds" Lake Qqnstance. The limestone of.tbe.-Dan-a abe Valley is composed- of irregular • layers diversely inclined, very friable, -stratified, split/rind divided. The soil is so permeable, that it absorbs the .greater nupaber of springs and* streams which rise between the Aach aod the Danube. For many years it has been noticed tbat the Danube loses a portion , bf. its water, in this region, and that during' dry seasons even the greater., 1 part of its" flow disappears in crevic.es ! or veritable hole3 io ita bed. The owners of factories situated on the = .Danube, iu order to retain their water supply stopped up these leaks, but in doing so tbey were at onee opposed by the manufacturers who were located on the Aach, the latter claiming tbat the water lost by the Danube* fed : the Aach and to check the waste frora one river to -the^^ other was to interfere with their just enjoyment of the smaller stream. The question, however, was to prove that the assertion of the Aach manufacturers waa a; true one,: namely, does the water from the Danube, by some subterranean infiltration, supply the Aach, located, as already stated nine milea away ? The first plan euggeated was to make the Danube water salt. Thiß waa proposed by Professor Knop, of Karlsruhe, and accordingly 22,0001be. of salt, were "placed in a hole in the great river. Then water from tbe source of the Aaobe was obtained every hour for leveral days, and this on being analysed, revealed the presence of the 7 salt. In order to get still better proof, M. Ten Brink deoided to take advantage of the wonderful colouring power of fluorescine. This aubstanoe is the first of a series of superb colouring matters, according aa there 15 introduced. in to its const'itu^ v 'iid'^bl^teiobV ibdirfe^ ri ob'lor ine 9 and ita. fldloonng power la eo '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 in.the bed of the Danube. Oo October 12, the observers stationed at the source of the Aach observed the 'coloration of the water. It had, therefore, taken about sixty houra for the coloured water to traverse the soil and re-appear. It is stated that the Aach as it gushed from its springs presented a magnificent intense green, which in the jsun exhibited more more or less fluorescent reflections ranging from light green to brilliant yellow. The intensity of the dye augmented from morning until evening of October 12. Its effects were quite visible Until about 3 p.m. on the 13th, when it gradually jdisappeared. The experiment was .certainly a most remarkable one. ■- j Its repetition in other localities may pi-ove of great value in the study of subterranean water-courses, while it offers a new method of geological investiga^ tion worthy of general attention.'