Feb 20. 1S>5.] 



KNOWl.I-^, r 



1-J5 



scale, and an embankment uboul loOff. liighforniod to take 

 the place of the destroyed tunnel. Tl:e now bank behind the 

 slipped Ujatcrial was very higli and ^t(ep, but as there was 

 not time to secure it conipUtely, as it was desired to 

 re open the lino for trallio inmicdiately, the protecting works 

 were resiricttd to a certain amount of dry wa'ling, where 

 the marl rock pnjected most dangerou>Iy, the remainder of 

 the surface being protected against rain and snow by a 

 coating of tar. As the bank is abont 7."> yards long, and 

 lises from SO ft. to 100 ft. above the rail level, a force- 

 pump and hose were employed to distribute the tar uni- 

 formly ever the entire suiface. The black cliti' so produced 

 has become a noticeable, if not a very mlivcniiig fea ure in 

 the scenery of the line; while for iis particular purpose — 

 that of a temporary protection (f the ground — it has 

 answered very well, the tar covering not having suilVred by 

 the heat of tlie summer of 1884. This is in part due to 

 the fact that the clilf is only exposed to direct sunlight 

 during a short time in the day, as the river gorge is very 

 deep and narro^r. Smaller local slips have been stopped in 

 a similar way by a further coating of tar. 





CR.'.:^•.■•, 



To allonr for the inevitable subsidence of the new em- 

 bankment, the rails have been laid upon a grating formed 

 of three superposed layers of slee])ers, ]daced alterLately 

 parallel and perpendicular to the axis of the line. 



Soon after the reopening of the line in March, 1883, 

 the permaLent drainage works were comraecced. These 

 consisted i^f levels, mo.^tl}' of elliptical cross-section, from 

 5 ft. to 7ift. high and 3i fc. to 5 ft. wide, lined with 

 masonry or concrete, which are driven into the bank from 

 near the river level, generally perpendicular to the direc- 

 tion of the line. Although nearly a mile of these galleries 

 had been driven up to November, 1881, the result v ai un- 

 satisfactory, as no large amount of water was tapped, and 

 small tlips were continually occurring on the I ank, until 

 about the middle of the month, when a side drift from the 

 No. 3 shaft, about 1.5 yards long, struck a cavern in the 

 limestone rock, which passed upwards in a kind of 

 chimney 70 ft. high, and downwards in an irregular gallery 

 or grotto, about 200 ft. long and ■15 ft. deep, terminating 

 in a small lake of undetermined dimensions, with 

 about 16 ft. depth of water close to the shore. The 

 walls of the grotto are covered with .stalactite.", while 

 those of the upper j.art or chimney are polished smooth 

 by the numerous pebbles in it, which are all of a per- 

 fectly spherical form, atid also well polished. The lake is 

 about 34 ft. above the river and the top of the chimney 

 about 114 ft. higher than the lake, which just brought it 

 level with the spring of the arch of the original tunnel, and 



about J35 ft 1)01 izontally distant from it, a position which 

 suthciently explains the constant iiillux of waUr, whioh 

 could ne\cr le Mitisfactoii'y accounted for by the original 



LONCIT'JDINAL EECTlC*: CF"-- 



:MPPEO 



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RiVCR RHOWE 

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£CAL£ roR HEiC.^TC A.\o Di^TANCi; i::;:o 



constructors of the Hue. The lake is evidently fed bv 

 numerous fissuies, traversing the limestone forming the- 

 mountain, and together witli the grotto and '\i» outlet, 

 forms a natural syphon. On the day of the great s-lip the 

 water must have riten through the whole height of 114f*',, 

 corresponding to a pressure of about 'i\ atuiospheri 8, 

 giving an enormous flow. Since the new drainage le el. 

 has been opened the discharge is very great, amountii g, 

 duiing the period of melting snows, to betwten 2,000 to 

 3,500 gallons jier second, which issues with such velocity 

 as to divide, and even to some ixteit keep back, the main 

 current of the Rhone. Ttie engiiieer in chariic of the 

 distriut, Monsieur Charbonnier, iiilcnds to pri.vulc u<x tl.e 

 permanent diainage by a new and shorter tuuin-l driven 

 directly up to the lake. 



The discovery of the cause of the accident has, so far, 

 been of value that it has pieventtd a large outlay upon an 

 alternative line, several of which — such as a transfer of 

 the line to the opposite bank of the river, a long turn el 

 under Fort de I'Ecluse, and even the complete abandonmi 1 1 

 of the line butween the Credo tunnel and tieneva, in favov.r 

 of a direct connection of the Bellegarc'e and Evian lire 

 with the City of Geneva — were jiroposed and under cor- 

 tideratiun forsimie time. The cost of resti>)-irH_; the port!' is 

 of the line destroyed by the slip is estin ated at about 

 XGO,000, and the losses by the stoppage of the traf! e 

 may be es;timated at about the same sum in iiJditior. — 

 En2ine,er. 



\\ 



THE ORIUIN OF COAiETS. 



Bv RiCIIAUD A. Pkoctoi!. 

 r^NCKE'S Comet has leturred to our nfigldiourhcocL 



li and is now under observHtinn. Yet to all ordirary 

 appearance our skies are urchangtd. Those who associate 

 the return of a comet with the ajipearance of an awe- 

 inspiring oViject, with hng, sword-Jikc tail brandishe<! 

 athwart the heavens, like tliose comets which have in past 

 and recent ages terrified the nations, are di^appoirited 

 when they hear that the comet of which the papers spcjk, 

 and which Professor Young re-discovered a few days rgf, 

 and our teh scopists are carefully observing, is one which 

 cannot even be seen without telescopic aid. Yet to the 

 stu'hnt of astrononjy the triumph is greater wlicn one 

 small comet is caught in the toils of inalhemalical analysi", 

 and detected as it advances along its relurri track, than 

 when the niost glorious row comt t blazes in our ski's, and 



