23S 



NA TURE 



[July 5, 1894 



through which the Niagara canon has been cut. The drainage 

 of ihe tableland in ancient times was across the direction of 

 the Niagara liver, and was strongly marked by bold limestone 

 ridges, which have only been penetrated by the Falls in modern 

 times. Even the Erie basin emptied by a route several miles 

 we«t of the Niagara. 



The basement of ihe present river channel is described, and 

 Ihe discharge estimated. Attention also is called to the fact 

 that during a considerable portion of the life of ihe river, only 

 the waiers of the Erie basin, or 3/1 1 of the whole drainage of 

 the great lakes, passed over the Falls. 



From four surveys, extending over a period of forty-eight 

 years, the mean modern rate of recession of the Falls is found 

 to be 4175 ft. a year. Its rate is varable with secular episodes 

 of rapid medial recession, followed by its cessation along the 

 axis, but with increased lateral retreat. This cycle appears to 

 lake about fifty years. This rate is, however, excessive, on 

 account of the geological conditions favouring the rapid modern 

 recession, but the rate taken for the mean recession under the 

 conditions of the modern descent of the river with the present 

 discharge is 375 ft. a year. 



At one time a great proportion of the lake region was 

 covered by a single sheet, or the Warren water. Upon its 

 dismemberment — in part, at least, by the rise of the land — one 

 large lake was formed occupying ihe basins of Huron, Michi- 

 gan, and Superior ; and another a portion of the Erie extend- 

 im; into the Ontario basin. The waters in these two basins 

 were subsequently lowered, so that they fell to their rocky 

 eastern rims ; the three upper lakes discharged by way of Lake 

 Nipi>sinc and the Otiawa river, and the Niagara had its 

 birth, draining only the Erie basin. Then the Is'iagara river 

 descended 2CX3 ft. In course of time the waters subsided 

 220 ft. more, but eventually they were raised again 80 ft. at Ihe 

 mouth of the Niagara, thus reducing the descent of the river 

 from the head of the rapids above the falls to the foot of the 

 last rapids in its course to the lake to 320 ft. During the 

 lowest stage, Ontario lake receded twelve miles from the end 

 of Niagara gorge, where the falls had been located at their 

 nativity. 



After a discussion of the laws of erosion, the author sketches 

 as follows the history of the Niagara Gorge and Falls : — 



First episode; Water falling 200 ft., in volume, 3/11 of 

 modern discharge; gorge, 11,000 ft. long; duration, 17,200 

 years. Second episode : river descending 420 ft., in three 

 cascades ; first stage, only the discharge of the Erie waters ; 

 length of chasm, 3000 ft. ; duration, 6000 years ; second stage, 

 drainage of all the upper lake ; length of chasm, 7000 fi. ; 

 duration, 4000 years. Third episode : same volume and descent 

 as in la»t, but the three falls united into one fall ; length of 

 chasm, 4000 ft. ; duration, Sooyears. Fourth episode : volume 

 of water as at present, the level of lower lake as to-day ; first 

 stage, a local rapid making the descent of 365 ft. ; work par- 

 ticularly hard ; lenglh of gorge, 5500 ft. ; duration, about 1500 

 years; the second stage as at present; work easy; Icngih of 

 canon, 6000 fl. ; descent of water, 320 ft. ; rale of recession 

 here taken as the full measured amount of 4175 ft. a year ; 

 duration, 1500 years. Thus the age of the Falls is computed 

 to be 31,000 years, with another loco years as ihe age of (he 

 river before the nativity of the Falls. The turning of Ihe Huron 

 waters into Ihe Niagara was about 8coo years ago. .\ difficult 

 qucjlion was the amount of work done in each episode. This 

 was in part determined by the position of the remaining terraces 

 corresponding 10 different stages of the river, and by the chang- 

 ing effects of erosion. 



The'C terraces in the lake region have been deformed by un- 

 e'|ual terrestrial elevation, to which the changing conditions of 

 the river arc largrly due. The deformation affecting the Niagara 

 district, since the commencement of the river epoch, amounts 

 to 2'5 fl. per mile ; east of Lake Huron, 4 ft. per mile ; and at 

 the outlet of Lake Ontario, 5 ft. per mile; all in a north- 

 eastward direction. Taking the amount of movement in each 

 district ai representing also the proportional measure of time, 

 ihcn calculations can be made upon several of the beaches, anil 

 in terms of the age of Niagara their antiquity can be inferred. 

 Jn the application of these results it appears that the rate of 

 terrestrial uplift in ihe Niagara district is about I 25 fl. a 

 century ; 2 fl. east of Lake Huron, and 2'5 ft. at the outlet of 

 Lake Ontario. 



The c beaches lead 10 the conclusion that the beginning of 

 llie lake age was about 64,000, or possibly 80,000 years ago ; 



NO. 1288, VOL. 50] 



assuming that iis waters were not held up by ice-dams. If that 

 were so, the date would be much less remote. If the present 

 rate of uplift continues, the Falls will be brought to an end, 

 before ihey have reached Lake Erie, by the diversion of the 

 waiers of the upper lakes, by way of Chicago, to the Mississippi, 

 which change might be expected 7000 -Sooci years hence. 



June 14. — " Flame Spectra at High Temperatures. Part IL 

 The Spectrum of Metallic Manganese, of Alloys of Man- 

 ganese, and of Compounds containing that Element." By W 

 N. Hartley, F.R.S. 



The spectrum of manganese has been ihe subject of much 

 investigation ; the spark spectrum was examined by Huggins, 

 Thalen, and^ Lecoq de Boisbaudran ; the arc spectrum was 

 studied by .\ngstr6m, Thalen, Cornu, Lockyer, also Liveing 

 and Dewar ; the flame spectra obtained from compounds of 

 manganese were investigated by Simmler, Von l.ichlenfels, 

 Lecoq de Boisbaudran, and Lockyer, while Marshall Watts has 

 given us accurate measurements of the wave-lengtlis of lines 

 and bands observed in the spark andoxyhydrogen flame-spectra 

 of Spiegel -eisen, manganese dioxide, and other compounds of 

 this metal. 



Photographs of the spectra of metallic manganese and of 

 manganic oxide were taken and compared. They were also 

 compared with the spectra of ihe alloys of manganese. The 

 periods of exposure varied from a mere tl.^sh in the case 

 of spiegeleisen when being poured into a Bessemer converter, 

 to 30 minutes and even as much as 80 minutes with manganic 

 oxide. 



The leading features of the spectra of manganese and 

 manganese oxide are the same, but they difTer in detail, as may 

 be observed by comparing the wave- lengths of the lines and 

 bands in their respective spectra. 



.■\ striking group of lines, the most persistent in the whole of 

 these spectra, is situated in the violet. The following measure- 

 ments were made : — 



4036'5 40349 Angstrom, also Cornu. 



'»°32-° [toiX) Angstrom. 

 40295 40294 Angsttiim. 



June 21. — " A Contribution to the Study of (i.) some of the 

 Decussating Tracts of the Mid- and Interbrain, and (ii.) of the 

 Pyramidal .System in the Mesencephalon and Bulb." By Prof. 

 Rubett Boycc. 



Chemical Society, June 7. — Dr. Armstrong, President, in 

 the chair. — The following papers were read: — The crystallo- 

 graphy of the normal sulphates of potassium, rubidium, and 

 ca-sium, by A. K. Tutton. The author shows that the whole 

 of the crystalkigraphical properiies of the strictly isomnrphous 

 rhombic ncrmal sulphates of potassium, rubidium, and caesium are 

 (unctions of the atomic weight of the metal which they contain. 

 — C)bservati()ns on ihe nature of phosphorescence, by H. 

 Jackson. The phenomena of fluorescence, of phosphorescence in 

 air on exposure to light, and of phosphorescence of substances 

 in a vacuum under the influence of the electric discharge, 

 seem to be of the same (>rder, and consist in a response on the 

 pari of Ihe substances to ihe operation of r.idianl energy propa. 

 gated after the manner of light in undulations of short length. 

 — Note on the viscosity of solids, by J. Dewar. The author h.is 

 investigated the viscosity of solid substances by forcing Ihem 

 through a narrow orifice by means of a hydiaulic press ; many 

 substances, such as crystalline sodium sulphate, aminnniuni 

 chloride, graphite, urea, sv:c., easily flow uhiIlt a pressure of 

 30-40 Ions pressure on the square inch .\ number of sub- 

 stances, such as starch, sodium chloride, &c., could not be made 

 to flow into wire under a pressure of 60 tons on the S(|uarf 

 inch. — Boiling points of homologous compounds ; part ii., byj. 

 Walker. The formula T = a Si' which the author has pre- 

 viously used to represent the boiling points of members of homo- 

 logous series is now applied 10 a number of other such scries. 

 — The action of methyl irulide on hydroxylaminc, by W. R. 

 Dunslan and E. Gouliling. Attempts to pnpaie /8-melh)l- 

 hydroxylamine hydriodidc by the action of melhyl io<Iide on 

 hydrox)lamine, as described by L. dc Bruyn, were unsuccess- 

 ful ; the main product of the reaction is a Irimeihylhydroxyl- 

 aminc salt. — The reduction products of nitro-compounds, by 

 W. K. Dunstan and T. S. I))mond. The action of various 

 weak reducing agents on aliphatic nilro-compounds is being 



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