June 22, 1893] 



NATURE 



.87 



the influence of ice sheets on the geographical distribution of 

 plants. Prof. Thomas Meehan, the father of the latter, in a 

 " Catalogue of Plants collected in July, 18S3, during an Ex- 

 cursion along the Pacific Coast in South-eastern Alaska," ' had 

 given reasons for believing that plants did not merely advance 

 in the wake of retreating glaciers, or push into growth from 

 material brought down in their advance, but that when caught 

 under the mass of flowing ice, would remain for an indefinite 

 period, retaining vitality, and push again into growth when the 

 ice retreated. Prof. Meehan was led to this conclusion from 

 finding no annual plants among those collected in the immediate 

 wake of retreating glaciers in Alaska, while the actual number 

 of species of perennials collected in such locations would be as 

 great as if much time had been given for a floral advance. He 

 had but little opportunity for actual observation as to the plants 

 brought down with the earth carried on the ice, but so far as 

 this went only Epilobiiim latifoliutn and Dryas octopetela were 

 found in this condition, and scarcely any plants were observed 

 on recently deposited moraines. These and some other facts 

 led to the hypothesis that the plants were not migratory, but 

 had held their position through the whole icy period. 



These facts were supported by the determination of the ex- 

 istence of much the same flora in isolated spots of land recently 

 bared by the neve of the inland ice, as grow away from the 

 margins of the ice sheet, while the finding of living willow 

 trunks, grass, and perennial plants of many years' growth close 

 to the edges of retreating glaciers, seem to place the point 

 beyond any reasonable doubt, especially when, after careful 

 survey, through the construction and positions of the glaciers, 

 there was the absolute certainty that the plants could not have 

 been deposited by lateral, medial, or terminal moraines, though 

 they might have been by ground moraines — a circumstance 

 which would settle Prof. Meehan's position affirmatively beyond 

 dispute, since the ground moraines are borne under the flowing 

 ice rivers. Abundant vegetation was also found in nunataks^ 

 peaks of land projecting above the glaciers or ice cap — but little 

 significance was placed on this circumstance, since all such 

 nunataks visited were within a reasonably close proximity to 

 the main land masses, and the vegetation might readily have 

 sprung from seeds blown there by the winds or brought by mud 

 on the fee', of birds. But the demonstration of aged living 

 plants in the other situations named must have a strong bearing 

 on the discussions involved as to the influence of the ice age on 

 the distribution of plants over the surface of the earth. 



The abundance of lichens is characteristic of the flora of Green- 

 land. Rocks supposed from a distance to be naturally coloured 

 are found on closer inspection to derive their hue from a com- 

 plete investiture of some lichen. In this particular the crimson 

 cliffs, beginning at Cape York and extending many miles north- 

 ward, are a conspicuous example. These cliffs, rising sheer 

 from the water's edge to heights of from seventeen hundred to 

 two thousand feet or more, though of grey granite, show no spot 

 of the intrinsic colour even on being nearly approached, but 

 present a uniform red appearance over their whole surface from 

 a large orange red lichen which covers them. 



In view of Schwendener's theory that lichens are but symbiotic 

 forms of alga- and fungi, it is to be regretted that the probably 

 rich fields afibrded by the latter named great families in this 

 region have yet to be investigated. 



Mosses are even more abundant than lichens. They grow in 

 such vast quantities in spots, that their light or dark greens are 

 visible often for some miles away, brightening the otherwise 

 bleak shores wonderfully. Their persistence in growth under 

 apparently adverse circumstances is also remarkable. No 

 obstacle save the sea seems sufiicient to stop their progress. 

 l'>en dead glaciers have been and are being buried under the 

 steady march of these cryptogamous plants. Mosses fulfil the 

 same duty in Greenland that other forms of plant life perform in 

 more favoured climes, and the amount of rich vegetable matter 

 being deposited by them may be of great value in the future of 

 that great arctic island. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 

 The Rev. Bartholomew Price, Master of Pembroke College, 

 has been added to the electors to the Savillian Chair of 

 Astronomy on the present occasion. 



' Proceedings of the Academy of Natural Sciencej of Philadelphia, 1884. 



NO. 1234, VOL. 48] 



Sir Henry Howorth, F.R.S., has had the honorary 

 degree of D.C. L. conferred upon him by Durham University. 



Oxford has conferred the degree of M. A. upon Dr. W. B. 

 Benham, Aldrichian Demonstrator. 



Mr. W.Fisher, late Conservator of Forests in the North- 

 West Provinces of India, has been appointed Assistant 

 Professor of Forestry at Cooper's Hill. 



SCIENTIFIC SERIALS. 

 American Journal of Science, June.— Electro-chemical effects 

 due to magnetisation, by George Owen Squier. — Nikitin 

 on the quaternary deposits of Russia and their relations to pre- 

 historic man, by A. A. Wright. A summary of the views laid 

 before the International Congress of Archa;ology in Moscow, 

 1892, by the Russian geologist, Mr. S. Nikitin, regarding the 

 palaeolithic and neolithic epochs in European Russia, and their 

 coincidence with the geological divisions of pleistocene and 

 modern. — Rigidity not to be relied upon in estimating the 

 earth's age, by Osmond Fisher. A criticism of Mr. Clarence 

 King's estimate of the probable age of the earth on the ground 

 of its assumed rigidity not being an established fact. The argu- 

 ment derived from tidal action is fully discussed. Had the 

 solid part of the earth so little rigidity as to allow it to yield in 

 its own figure very nearly as much as if it were fluid, there 

 would be very nearly nothing of what we call tides -that is to 

 say, rise and fall of the sea relatively to the land — but sea and 

 land together would rise or fall a few feet every twelve lunar 

 hours. This would be the case if the geological hypothesis of a 

 thin crust were true. This is the argument for tidal rigidity as 

 enunciated by Kelvin. But this does not take into account the 

 horizontal motion of the water. It rests upon the equilibrium 

 theory of tides as against the canal theory. The latter has been 

 symbolically worked out by Prof. G. H. Darwin. If the 

 earth's interior be assumed to be a liquid of small viscosity, the 

 bodily tide at its equilibrium value will have a height of if feet. 

 This will diminish the hydrodynamical tide by not more than a 

 filth of its value, and it is quite possible that the tides we 

 actually experience may be tides thus diminished by the fluidity 

 of the earth's interior. — On the treatment of barium sulphate in 

 analysis, by J. I. Phinney. The author shows that alkaline 

 chlorides contaminate barium sulphate thrown down in the pre- 

 sence of an excess of sulphuric acid, and that the process of 

 purifying by hydrochloric acid is inefficient. The only good 

 method for purification is either to fuse, according to Fre^enius, 

 with sodium carbonate, extracting and reprecipitating as sul- 

 phate, or to evaporate from solution in concentrated sulphuric 

 acid according to Mar. — On the nature of certain solutions and 

 on a new means of investigating them, by M. Carey Lea. The 

 solutions in question are those of sulphates which were tested 

 for free sulphuric acid by a solution of iodoquinia, a very deli- 

 cate and trustworthy test. Solutions of heavy melallic sul- 

 phates, with the exception of ferrous sulphate, contain no free 

 acid. All sesquisulphates examined were dissociated in solution. 

 So were acid salts and aluins, with the exception of chrome 

 alum. — Also papers by Messrs. Fairbanks, Moses, Penfield, 

 Johnson, and Pupin. 



Bulletin of the New York Mathematical Society, vol. ii. No. 

 8 [May, 1893, New York]. This number opens (pp. 175-178), 

 with a review by Miss C. A. Scott of Prof. W. B. Smith's 

 "Introductory Modern Geometry of Point, Ray, and Circle " 

 (see Nature, vol. xlvii. p. 532). We endorse her closing remarks 

 that the usefulness of the book would be greatly increased if he 

 were to translate his work into ordinary mathematical English. 

 — Prof. Echols contributes an interesting note, biographical 

 and otherwise, entitled Wronski's expansion (pp. 178-1S4). The 

 expansion was presented by Hcienc Wronski in 1810, to the 

 French Academy of Sciences, and is as follows :^/(.r) = (7„ !- 

 a^wi + a«u.,+ ...ad in^uitum, where H^), »., ai2,...are arbitrary 

 functions of jr, and a,,, a,,... are independent of. r. The law of for- 

 mation of the coefficients he calls " la loi supreme." — Dr. Cole, 

 in a note on the substitution groups of 6, 7, and 8 letters (pp. 

 184-190), furnishes a list of over forty omitted groups supple- 

 mentary to the lists given by Messrs. Askwilh and Cayley in 

 vol. xxiv. of the Quarterly Journal of Mathematics. — The Ma- 

 thematical Bibliography, byA. Ziwet(pp. 190-192) gives in some 

 detail an account of the new Kevue Semestrielle <ies Publications 

 .hath^maliques, &c., issued by the Mathematical Society of 



