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by Mr. Owens's excavation. The disjointed stones of the T. C. Chamberlin, outlined in a former number of NATURE upper part of the stairway (some of which have already been (September 16), was avowedly altogether speculative, and be. cleared away) had slid down bodily from above and, until the longed to the domain of earth-physics rather than to geology in excavation was made, had completely hidden the lower part of the ordinary sense. The other was that in which Dr. J. W. the stairway.

Spencer ably advocated his well-known views on the continental It is to be hoped that the next part of the llemoirs of the elevation of the Glacial epoch. Peabody Instilute will give the details of this interesting work, Dr. Spencer described a large number of drowned valleys, and a more accurate (if less ambitious) drawing than that of the often extending from the mouths of the great modern rivers across “ restored stairway published in the Century Magazine. If the submarine plateaus at various depths, reaching to even 12,000 it has been possible to preserve the continuity of the inscription feet or more, and recognisable as far northward as Labrador. on the steps, Mr. Gordon's labours will have added to our store He stated that upon tracing northward the deposits occupying one of the longest and most valuable inscriptions yet found in the great valleys, he found that glacial accumulations occur in Central America.

New Jersey between the Lafayette formation, which is the latest Surely it is through an unintentional error that the drawing horizon dissected by the great valleys, provisionally regarded as of the Jaguar stairway, on page 409 of the Century, is ascribed of late Pliocene age, and the Columbia formation, which is midto Henry Sandham.

A. P. M. Pleistocene. From all these considerations he concluded that

the eastern portion of North America stood more than two miles

above the sea during the earlier Pleistocene epoch. RECENT PAPERS ON GLACIATION.

On other evidence he judged that the Mexican plateau was

mostly depressed to near sea level during the times of the high AT the Toronto meeting of the British Association the elevation of the eastern portion of the continent; and that, with

numerous papers bearing on the glaciation of the North the subsidence of the eastern region, the western side of the American continent were of exceptional interest to the British continent was elevated from 6000 to 10,000 feet or more. The student of glacial geology, inasmuch as they brought pro. separation of the Atlantic and Pacific Oceans he regards as only minently to mind the methods adopted by the Canadian and of recent date. These changes of levels and the dependent American glacialists, which differ in many respects from those variations of currents, &c., seem, in his opinion, to be sufficient to which we have become accustomed on this side of the cause for the Glacial period. Atlantic.

As Dr. Spencer pointed out, his views are practically those In no branch of earth-lore is the influence of his environment which have been advocated by Lyell and many others. But more strongly impressed upon the worker than in stratigraphical while a pre-glacial elevation of the North American continent is geology, and the effect of the simple topographical forms and of generally acknowledged by geologists, the extent of this elevathe enormous extent over which the glacial deposits are distributed tion is not usually admitted to have been even approximately as in North America, has been to give a broader grasp and bolder large as Dr. Spencer would claim, and the difficulties in account. tone to the general run of its glacial literature. This was admir. ing for the widespread glaciation of the Northern Hemisphere ably illustrated by the work brought forward at the meeting. In by the effects of elevation alone are so great that the defenders of the British Islands, from the abundance of natural and artificial this hypothesis are at present few. sections as well as from the complexity and narrow limits of There is a somewhat remarkable blank in the evidence to hand the topography, the lithological composition of the drist in North America as to the conditions immediately antecedent deposits is usually made the pivot of the studies, while in to the Glacial Period, nothing equivalent to the Forest Bed America it is rather the arrangement of the drist in regard to Series and associated pre-glacial deposits, of which we possess the general physical features which is held to be of paramount such excellent sections on our Norfolk coast, having yet been dis. import.

covered. For this reason the paper of Mr. R. Chalmers, of the The following comments on the papers read at Toronto have Geological Survey of Canada, on the pre-glacial decay of rocks been written from the standpoint of a British glacialist anxious in Eastern Canada, was of especial interest. Mr. Chalmers to find wherein he might profit by the adoption at home of the showed that in the region he described, beds of decomposed rock, Transatlantic methods.

of variable thickness and more or less modified, occur wherever To realise the extent of the field in North America it must be the surface of the rocks has not been abraded by Pleistocene ice, remembered that the total area of the Dominion of Canada, though boulder clay may often be found overlying them. about 3,616,000 square miles or not much less than the He gave the following general section of these beds in descend. whole of Europe, can show, in one form or another, traces of ing order :-(1) Transported and stratified water-worn gravel the Great Ice Age in every part, and that the same glaciated with beds of fine sand and clay. (2) Coarse stratified gravels, area further extends over a region about one-fifth as large to the usually yellow and oxidised, the materials wholly local. (3) southward of the Canadian border. It is not surprising, then, Sedentary rotted rock, passing into solid rock beneath. that the study of glacial phenomena should have attracted so There seems at present to be no evidence as to the precise many able workers in Canada and the United States.

age of these beds in Eastern Canada ; but Mr. Chalmers The exploratory work of Russell, Wright and others upon the pointed out that somewhat similar deposits occurring at the existing glaciers of Alaska, and of Chamberlin, Peary, Barton western base of the Green Mountains in Vermont, have yielded and others upon the edge of the ice-sheet in Greenland has been vegetable remains by which Lequereux, many years ago, more readily assimilated by American than by British glacialists, referred them to the Miocene. He concludes that the general and its influence is perceptible throughout their researches. It aspect of the dry land in Eastern Canada previous to the is true that the Danish explorers had already made known to us Glacial period must have been nearly similar to that of the the leading facts relating to the latter region, but their studies region south of the glaciated zone in North America. were not perhaps made so directly from the standpoint of the The occurrence of similar local rubble in sheltered situations glacial geologist as those of the above-mentioned observers, nor beneath the drift has often been noted in the British Islands, and were their results so accessible to the English-speaking geologists. the ease with which such loose-lying material would become But since Russell, by his investigation of the Malaspina Glacier, incorporated into the basal layers of an advancing ice-sheet has with its forested moraine covered margin sheltering a varied been frequently discussed. On both sides of the Atlantic it fauna and fora, has shown how widely different are the con- seems more probable that the greater bulk of the glacial ditions of Piedmont ice and Alpine glaciers, and since Chamberlin, in describing the mode of occurrence of the detrital matter direct erosive action of the ice upon the solid rocks. in the basal layers of Greenland ice-tongues, has thrown so much With regard to the initial stages of the glaciation, while the new light on the whole question of drift-deposition, the British European glacialist looks to the highest ground in the northern glacialist would do well to recognise, with his colleagues across part of his continent and its islands-to the mountains of the Atlantic, that the glaciers of the Alps do not afford the best Scandinavia, of Scotland, England, Wales and Ireland, and of introduction to the study of glacial geology. It is clear that Switzerland—as the great gathering grounds, it is generally the Alpine conditions are, in many respects, very different from recognised that in North America, with the exception of the those under which the ice-sheets of the Glacial period did Cordilleran mass in the extreme west, the glaciation commenced their work.

and spread from the comparatively low ground in the north of As regards the cause of the Great Ice Age, we heard at the the continent and moved southward against the slope of the Toronto meeting two interesting communications. That of Prof. land, the mountains near its south-eastern margin being

ment.

obstacles in its course rather than aids to its accumulation. It ledged that, given a sufficiently low temperature, the prime is, indeed, probable that in Eastern Europe too much stress has factor in the accumulation of the ice-sheets has been the exces. been laid on the importance of the hill-ranges as glacial centres, sive snowfall rather than the extreme cold, may not the wholec since there is much evidence to indicate that, at any rate the phenomena have been due to the gradual shifting of the during the maximum glaciation, the movement, and probably areas of greatest precipitation, brought about, as a secondary therefore the growth, of the great sheets was more or less effect, by the growth of the ice-sheets themselves? independent of the orographic features. In this connection the It will be observed that Mr. Tyrrell, in common with a'] explorations of Mr. J. B. Tyrrell, of the Canadian Survey, in American glacialists, has recognised an up-hill movement of the that birthplace of ice-sheets the desolate region to the westward ice sheet. The possibility of such movement has frequently been of Hudson Bay, are of the highest importance. In his paper questioned on our side of the Atlantic, in spite of the occurrence on the glaciation of North-western Canada, Mr. Tyrrell stated of transported boulders in various parts of the British Islands a: that no evidence was discovered of any great elevation of this levels considerably higher than their source. But the extent of central area in Glacial, or immediately Pre-glacial times, and the uplists in such instances is slight as compared with that it would seem not improbable that the land then stood at about described by Prof. C. H. Hitchcock in his paper on the Southern the same height above the sea as at present ; and that the Lobe of the Laurentian Ice-sheet. moisture giving rise to the immense precipitation of snow would Prof. Hitchcock pointed out that one great lobe of the Laurenprobably be derived from the adjacent waters of Hudson Bay tide Glacier went southward through the Champlain am and the Arctic Ocean.

Hudson valleys, moving from a plain near sea level, over the In the region immediately west of Hudson Bay, the earliest highest mountains in New England and New York, 6000 and glaciation of which he could recognise any traces flowed outwards 4000 feet in altitude, as shown by the transport of the boulders from a gathering.ground which lay north or north-west of and by the direction of the glacial striæ. “As indicative of the Doobaunt Lake. Subsequently this gathering-ground moved distinctiveness of this lobe he described how the striæ diverge south-eastward, until it centred over the country between from the central line “much like the barbs of a feather from the Doobaunt and Yath-kyed Lakes. From on

one or other of these central shaft,” and how the terminal moraines are looped round centres the ice seems to him to have flowed westward and the area rudely at right angles to the direction of the ice more. south-westward to within a short distance of the base of the

The initial gathering ground for this portion of the iceRocky Mountains ; southward, for more than 1600 miles to the sheet seems to have lain to the eastward of Hudson Bay: States of Iowa and Illinois : eastward, into the basin of Hudson hence it is sometimes termed the Labradorian Glacier. Bay; and northward, into the Arctic Ocean.

The lobate character of the southern termination of the ice Ile applies the name Keewatin Glacier to this central con

on and the tendency of these lobes to spread outwards from a centre tinental ice-sheet, which in general character appears to have is strongly insisted upon by all the American glacialists who been somewhat similar to the great glacier of north-western have studied the peripheral portions of the glaciated area, and Europe, with a centre lying near the sea-coast, a steep and the delimitation of these lobes and the discussion of their short slope seaward, and a very much longer and more gentle chronological relations has been made the subject of much recenit slope towards the interior of the continent. But, remarked

research. The matter is worthy of more attention than it has Mr. Tyrrell, there was this difference between the two, that the yet received with us, for as was shown by Mr. H. B. Woodward centre of the latter was over a high rocky country ; while the in a paper, read at Toronto, on the Chalky Boulder.clay of our centre of the former was over what is now, and was probably Wesi-midland counties, some at least of the characteristic phenoalso then, a low-lying plain, on which the snow accumulated to mena can be recognised in this country also. The fact that in such depths as to cause it to flow over country very considerably America these distinct lobes did not reach their maximum higher.

development at the same time, and that the overlapping of one This great glacier, in the different stages of its retirement great tongue upon the area previously occupied by another is down gradually descending slopes, caused many temporary frequently indicated, has given rise to much difference of opinion extra-Glacial lakes to be formed, which were drained one after as to the length of the time-interval separating these different another as it retired to still lower country. Before it had with. stages of growth and retreat. Prof. T. C. Chamberlin, who drawn from the Winnipeg basin, Mr. Tyrrell thinks that it was gave a lucid demonstration of his views at Toronto, is of joined by an advancing glacier from the east, and in front of the opinion that the glacial phenomena of the northern United two, Lake Agassiz, one of the largest of the extra-Glacial lakes, States indicate two or more successive and distinct periods of was formed. During the final stages, its general gathering: glaciation separated by mild interglacial intervals, while other ground is believed to have moved still nearer to the coast of observers are inclined to agree with Dr. G. F. Wright, wbo Hudson Bay, and to have broken into several separate centres ; though acknowledging wide oscillations of the ice-margin, and Mr. Tyrrell notes that after its retirement the land in the regards the growth and wane of a single sheet as sufficient to vicinity of Hudson Bay stood from 500 to 600 feet below its account for all the facts. present level, and gradually rose to its present height.

In America, therefore, as in Europe, in spite of the prolonged The shifting of the centres of glaciation at different stages of discussion, not only is the number of the supposed warm inter the Great Ice Age, to which Mr. Tyrrell referred, seems to be a glacial periods still unsettled, but the evidence for even one such well-recognised characteristic in North America, though it is interval is challenged. The whole question is largely a legacy diversely explained. Dr. G. M. Dawson, in the admirable from the brilliant theorising of the late Dr. J. Croll, and with summary of Canadian Geology in the new Handbook for the breakdown of his captivating generalisations it has become Canada prepared for the Toronto meeting, notes that the necessary to reconsider the whole evidence which has been western part of the Great Plains was invaded at an early stage adduced, in support of them, on both sides of the Atlantic, before by large glaciers issuing from the Cordilleran ice-sheet through a sase conclusion can be reached. It is suggestive that while the the main valleys of the Rocky Mountains, while at a later explorers of the peripheral areas of the old ice-sheets are usually period, when this ice had shrunk back, a newer series of glacial steadfast in their belief in such periods, those whose investigadeposits was spread out in the same area, largely composed of tions lie more centrally to the regions of accumulation, both in Laurentian and Huronian débris transported from the north- Europe and in America, are more frequently in favour of the

unity of the great glaciation. Yet even this localisation of Dr. Dawson, while acknowledging that the evidence is not opinion is capable of two opposite applications. satisfactory, is still inclined to think that these latter deposits may One of the strongest threads in the evidence for an inter-glacial be in part of marine origin, and that they indicate great relative period in North America is furnished by the sections in the and absolute changes of level in this region in Glacial times. vicinity of Toronto. Since Dr. G. J. Hinde described these

In eastern Canada also "it has been found by Mr. Chalmers deposits in 1877, fresh excavations in the Don Valley have that when the Laurentide Glacier invaded the lowlands to the revealed new facts of importance. Prof. A. P. Coleman, in his west of Quebec, the Appalachian glacier had either greatly paper on the subject at the British Association meeting, stated decreased or had vanished” (Handbook, p. 30).

that in the Don Valley a lowest till is seen, upon which rest 18 In England the drist deposits of the eastern and midland feet of sand and clay containing many unios and other shells counties show many similar indications of successive glaciation as well as leaves aud pieces of wood. Some of the unios de from different centres, and until recently the tendency has been,

are ably stated by

mberli as in America, to ascribe the facts to the intervention of warm

in the chapter on the

Glacial phenomena of North America in the third edition of Pro Jas. inter-glacial periods. But since it is now generally acknow. Geikie's " Great Ice Age."

east.

1

Prof.

sea.

not now live in Canadian waters, but are found in the Mississippi ; almost continuously, which is rarely possible. In certain and several species of trees now belonging to the States to the regions, however, the study has been carried on under more south occur with them, indicating a climate decidedly warmer favourable conditions, with most interesting results. Thus Prof. thin the present. Above this come stratified clay and sand, H. Leroy Fairchild, in describing the glacial phenomena of with a caribou horn and remains of insects and plants belonging

Western New York,' showed how the long upland valleys of to a colder climate than the present. This set of clays and sands that part of the State contain the terraces of lakes which is best shown in the cliff-section at Scarborough Heights a few have overflowed southward across the watershed, leaving wellmiles to the east, where the series rises 148 feet above Lake marked channels of glacial drainage, and how as lower passes Ontario, and contains many species of extinct beetles, as well as were opened by the retreating ice the waters of these lakes sank shell-fish, mosses, and wood of hardy trees. A complicated to corresponding levels. The highest of the continuous shoremiddle till overlies these beds which were deeply eroded before lines of this region is recognised as being that of the glacial Lake the advance of the ice. Another less important fossil-bearing Warren, which is believed to have stretched from the western bed occurs above the middle till at elevations up to 240 feet end of the basin of Lake Ontario over the whole or the greater above the lake, and is followed by a third till. Prof. Coleman part of the Great Lakes. 2 notes that great changes have occurred in the level of the water, Below this are found several less continuous terraces, probably the lake being much lower than at present before the first glacial marking different stages of the depletion of the lake, until at abɔut advance and after the first interglacial time, and that during the 500 feet lower the Iroquois shore-line is reached, which appears deposition of the middle till, and also while the last sheet of to have been the immediate forerunner of the Lake Ontario of till was being deposited, the water stood from 250 to 300 feet the present day. This beach is admirably developed in the above the present level of the lake, which is 247 feet above the vicinity of Toronto, and the main facts regarding it were de

In his opinion the length of time required for the first monstrated by Mr. Gilbert and Dr. Spencer during the meet. interglacial period is probably to be estimated at thousands of ing. Dr. Spencer considers that it is an old sea-beach ; but in years; and during this time he thinks the ice-sheet of the this he is at variance with most of the American glacialists, who Laurentide Glacier must have completely disappeared.

hold that it, like the higher beaches, is of fresh-water origin. As a result of this paper a British Association Committee was These old beach-lines are of especial importance in that they appointed to investigate these deposits further by means of

reveal considerable differential uplift during late-glacial and post. excavations. The palæuntological evidence is held to imply glacial times. On this point all the students of the subject are that, as above stated, the climate when the Don Valley deposits agreed, and it is, of course, regarded therefore as a factor of were laid down was such as would be incompatible with the prime importance in the later history of the lake basins. It was presence of ice anywhere in the Laurentide area, and that ihis insisted upon by Mr. F. B. Taylor in an interesting communiwarm period was followed by a later glaciation, of which the cation on the relation of the Champlain submergence to the clearest evidence is contained in the section at Scarborough Great Lakes and to Niagara Falls. Working on the same lines Heights. The identification of the warm-climate horizon in this as Mr. Gilbert had done, Mr. Taylor showed that an old shore. cliff-section is especially desirable, and is one of the results which line, named the Nipissing Beach, surrounds a large portion of may be hoped from the Committee's investigations.

the Upper Great Lakes, and leads to a low col at the east end In describing the drift phenomena of the Pacific coast around of Lake Nipissing. The formation of this beach he supposes Puget Sound, which in most respects compare very closely with to have been contemporaneous with the Champlain submergence those of our own islands, Mr. Bayley Willis put forward the by which the St. Lawrence Valley and the Champlain depreshypothesis that the channels of the Sound, which have usually sion became arms of the sea, so that during this period the been considered submerged valleys, are the hollows remaining Upper Great Lakes had their outlet by way of the Nipissing after repeated glacial invasion of a wide and diversified de- Pass and the Ottawa River into the St. Lawrence, leaving only pression, during which the earlier divides were built upon, and the discharge of Lake Erie, or one ninth of the total volume, to transformed into plateau like eminences of glacial drift, whereas occupy the Niagara River. Mr. Taylor stated that the Nipis. the occupation of the valleys by glacial ice, particularly in sing beach is tilted so that it falls regularly towards S. 27 W. at the stagnant stages of retreat, prevented their being per- the rate of nearly 7 inches to the mile, being 110 to 115 feet manently filled ; so that with the final retreat of the ice the above the present surface of the north-eastern part of Lake moulds of glaciers remained as the channels of the Sound. Superior, while not far east of Duluth it has sunk' to the water

This view accentuates the undoubted fact that the accumula. level, and if its plane were projected it would pass 100 feet tion of glacial debris has been greater around the margins of the

below the lake-level at Chicago. He gave reasons for considerold ice lobes than in the more central areas, and it may be applied ing that the tilting was caused by the same uplift which raised to some extent to our own islands, where the persistence since the Champlain Valley, and that one effect of this movement was pre-glacial times of the shallow basins of the North Sea and the to close the Nipissing outlet and to open that at Port Huron, by Irish Sea appears to indicate that a larger proportion of the which the entire discharge of the lakes was sent into the material transported by the ice-sheets which once filled them Niagara. The result of these changes is to be found, accordhas been deposited around their margins than within their beds. ing to Mr. Taylor, in the cañon below the Falls, the narrow and

The old lake.beaches, incidentally referred to by Prof. shallow gorge of the Whirlpool Rapids indicating the work of the Coleman and Mr. Tyrrell, occupy a large place in the studies of comparatively feeble stream from Lake Erie, while the Upper the American glacialists, while in the British islands, in spite Great Gorge has been excavated since the closing of the Nipis. of the rough pioneer work of the late Prof. Carvell Lewis, the sing outlet, which, accepting the known rate of recession of the subject has scarcely been touched. The scope for these Horse shoe Fall as the principal datum, may have taken place researches in our country is, of course, limited ; but the classical from 5000 to 10,000 years ago. example of the parallel roads of Glen Roy is sufficient to prove These researches may well serve to illustrate the complexity of that the phenomena are not unrepresented. In America two the problem whenever an attempt is made to transmute the term distinct types of old lakes have been recognised-those like of geological processes into an equivalent in years. Simple Lake Agassiz and Lake Warren, which were formed in front multiplication and division without a steady.going chronometer of the retreating ice-margin, and those like Lake Nipissing and can never suffice, nor is the time-unit that serves for a man's life Lake Iroquois, which owed their position to differential earth ever likely to help us much in measuring the duration of cosmic

processes. The literature in regard to both types is already very exten- As regards the differential movement, Spencer and Gilbert sive, and is not altogether satisfactory. Especially in the case are of opinion that it is still in progress, and will eventually subof the glacially-dammed waters, their reputed vast extent, their merge Chicago and dry up Niagara. In a recent paper 3 Gilbert impersistence of level and brief duration, the later modifi. has even ventured to predict in years when this may be expected. cation of their sites by earth movements, and above all the

G. W. L. obscurity of their traces over wide tracts of uncleared forest, " This paper is printed in full in the Geological Magasine, and is makes it certain that while the broad fact of their former exist- therefore easily accessible to British geologists. ence may be undoubted, the delimitation and correlation of their . An admirable summary of the work of Spencer, Gilbert, and others in boundaries must be regarded in most cases as more or less pro

elucidating the history of this great body of water will be found in a paper

by Mr. Warren Upham on “ Glacial Lakes in Canada,Bull. Geol. Soc. of visional. With gravelly deposits of all kinds spread 'over such Am., vol. ii. (1891) pp. 243-276. an enormous extent of territory it must necessarily be difficult

3 " Moditication of the Great Lakes by Earth Movement," U.S. Nat. Geo10 pick out an individual shore-line unless this can be traced

graphic Mag., vol. viii., September 1897, p. 233 (see NATURE, December

30, 1897).

movements.

occurrence

lodobromite

anoma

MIERSITE, A CUBIC MODIFICATION OF two specimens preserved in the British Museum collection are NATIVE SILVER IODIDE.

from ihe Broken Hill silver mines in New South Wales; the

associated minerals on one specimen are quartz, copper glanct, SILVER JODIDE is remarkable in being one of the few and garnet, and on the other, malachite, wad and anglesite

.

The small crystals of miersite, which do not exceed 2 mm. in temperature increases. This contraction is uniform until about

diameter, are scattered over the surface of the matrix ; they are 146° C. is reached, when there is a further sudden contraction of

of a pale or bright yellow colour, with an adamantine lustre. considerable amount, after which the substance expands. The

The only forms present are the cube and one or both of the sudden contraction at 146° is accompanied by a change in all

tetrahedra, the latter usually differing in size but not in surface the physical properties of the substance, the pale yellow, hexa

characters. gonal modification which exists at ordinary temperatures, being

In many respects the mineral is strikingly similar

to the yellow blende which occurs in the white dolomite of the then changed into a bright yellow, cubic modification. On

Binnenthal in Switzerland. The bright yellow streak is some cooling the reverse phenomena are observed. From this behaviour it would be expected that only the pale strikingly shown by perfectly colourless and transparent crystals

times deeper in colour than the crystals themselves ; this is yellow, hexagonal modification would be found as a natural

of marshite, which also give a bright yellow streak. Exposure mineral, and as a matter of fact the only pure silver iodide so far known is the hexagonal species iodyrite.

to bright sunlight for several days does not affect the colour of The existence of

the crystals. The silver is in part replaced by copper, and as a cubic modification has, however, long been suspected from the of iodine in the cubic mineral jodobromite site to marshite : "cuproiodargyrite” (Agl. Cul) from Chili is

this increases in amount, there is a gradual passage from mier(2AgCl. 2Ag Br. Ag]). This probably represents the artificial possibly an intermediate member of this group. cubic modification which is stable above 146°, in which case the

The new mineral has been named in honour of Mr. H. A. natural crystals of iodobromite should be pseudo-cubic ; in fact,

Miers, F.R.S., Professor of Mineralogy at Oxford, who first pseudomorphs of the hexagonal modification with the external form of the cubic modification. This would be strictly analogous correctly determined the

crystalline form of marshite, a mineral to the pseudo-cubic leucite and boracite, which become isotropic species are only to be distinguished by chemical tests.

so closely resembling miersite in appearance that the two when heated to a definite temperature.

L. J. SPENCER. The new mineral, miersite, is, however, quite distinct from these, and proves that silver iodide is trimorphous. The principal characters of the three modifications are :

UNIVERSITY AND EDUCATIONAL

INTELLIGENCE.
Iodyrite
Miersite

The Maryland Senate has passed a Bill granting 50,000

dollars a year for two years to the Johns Hopkins University. Hexagonal

Cubic
Cubic

DR. CHARLES Chree, Superintendent of Kew Ohservatory,
Hemimorphic
Tetrahedral

has received the honorary degree of LL.D. from the L'niversity Holohedral

of Aberdeen. Twin plane, a pyramid A tetrahedron face Not twinned face

MR. C. B. Rouss, who gave 25,000 dollars for a physical Cleavage, perfect basal Perfect dodecahe. Indistinct octahe.

laboratory building in the University of Virginia, has given an dral

dral

additional 10,000 dollars for the same object. Optically uniaxial Isotropic

Optically

MR. CHESTER W. KINGSLEY, oí Cambridge, Mass., has lous ?

given several large gifts to various benevolent purposes, including Sectile

Brittle
Sectile

the sum of 25,000 dollars each to the Newton Theological
Seminary, Andover Academy, and Colby University; the two

first named being situated in Massachusetts, and the last in Between these there is a remarkable crystallographic relation :

Maine. when a regular octahedron is considered as a rhombohedral

A COURSE of eight Yates lectures in Archäology will be comcrystal, the angle 70° 32' corresponds to the angle 70° 36' be.

menced at University College, London, on May 4, by Mr. J. tween the basal plane and a pyramid of iodyrite; the tetrahe. drism, twinning, and sometimes the peculiar development of the

Romilly Allen. The subjects of the first two lectures are the miersite crystals make this relation still more striking.

origins of primitive art and the evolution of decorative art, and Iodyrite, in all its crystallographic characters, is practically Celtic art.

the general object of the course is to trace the developments of identical with wurtzite (ZnS), greenockite (CdS), and zincite (250); these are all hexagonal and hemimorphic, possess a

The first school of forestry in America has just been created basal cleavage, and are optically positive, while the axial ratios by the legislature of the State of New York, to be connected with vary only very slightly (a :( = 1:0·8109 1:0·8196). Many Cornell University, and the sum of 10,000 dollars has been other substances may perhaps be included in this series, e.g. ice, granted to cover the expenses of the first year. The school is magnesium, cadmium iodide, tridymite (SiO2), dc. In the authorised to purchase forest lands to the extent of 30,000 acre same way the dimorphous cubic modifications miersite, blende in the Adirondack region. (ZnS), and marshite (Cul) form another parallel series, since The University of Paris has (says the Times) arranged for a they are all exactly alike in crystallographic characters.

loan of 1,700,000 francs from the Crédit Foncier, repayable in It will now be seen that the same relation exists between

50 annual instalments, for the erection of new buildings in Paris iodyrite and miersite as exists between wurtzite and blende. and at Fontainebleau. The Faculty of Science is also about to This forms, as far as crystallographic characters are concerned, order the construction at a cost of 25,000 francs of an equatorial, a perfect example of an isodimorphous group, but apparently which, after figuring in the Exhibition of 1900, will be placed the only relation existing between zinc sulphide and silver in the tower of the new Sorbonne. jodide is that their simplest conceivable chemical inolecules contain two atoms.

At the graduation ceremony of the Glasgow University on From these somewhat remarkable relations one is inclined to April 12, the honorary degree of Doctor of Laws (LL.D.; ask : why should there not be a third modification of zinc

was conferred upon Mr. Alexander Duncan, Secretary ard sulphide to correspond with iodobromite ? or why should not

Librarian to the Faculty of Physicians and Surgeons, Glasgow ; all these substances (2.3. ice, &c.) be dimorphous or trimorphous of Public Instruction, 'Cairo, Egypt ; Mr. John Inglis, formerly

Mr. Douglas Dunlop, Secretary-General to the Department to fill up the gaps in these parallel series? nantokite and marshite are to be represented by the formulæ president of the Institution of Engineers and Shipbuilders in Cu.Cl, and Cu,l, respectively, then miersite should be Agol, : Scotland, president-elect of the Institution of Marine Engineers

, these double molecules, however, only depend on the vapour

London ; Dr. Elie van Rijckevorsel, of the Batavian Society density of cuprous chloride, but the gaseous molecule cannot

of Experimental Philosophy, Rotterdam; and Prof. J. M. be the same as the crystal molecule, especially when there are,

Thomson, F.R.S., professor of Chemistry in King's College, as in silver iodide, possibly three types of the latter.

London. A detailed description of miersite will be published in the The excursions of the London Geological Field Class will Mineralogical Magazine. It may now be mentioned that the begin on Saturday, April 23, with a visit to Dorking, Box Hill.

dm =

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at

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and Betchworth; and between that date and the middle of July

EDINBURGH. the country from Aylesbury to Cuckfield will be systematically Royal Society, March 21.-Lord Kelvin, President, in examined by the class so as to draw a section over the trough of the chair.-Lord Kelvin, in a paper on thermodynamics, the Thames basin, and see the deposits to the north and south deduced from motivity, fulfilled a promise made twenty.one of London, which underlie the rocks associated with the chalk.

years ago to the Society. After referring to the somewhat' misThe class has been organised and carried on by Prof. H. G. leading phrase, the méchanical equivalent of heat, and pointing Seeley, F.R.S., for the past twelve years, without difficulty of out the necessity of having a single word to express the avail. any kind, and without assistance. It was established as a class ability of heat for transformation into useful work, he proceeded to show that systematic instruction in geology could be given in to show that the whole of thermodynamics was contained in the the open country, and the example it affords must tend to bring two equations about more practical teaching in the matter of field-work. When the class began there was very little of such teaching any.

de = JNdt + $(Pdg + JMdg)
t-T

-T where, but the value of individual observation is now accepted

= J as a canon of scientific education, and the success of Prof. Seeley's work should encourage educationists in their endeavour

where e is the energy, m the motivity, t the temperature of to get the fact knowledge entirely substituted for the word-know- any part of the system, T the lowest temperature in the ledge of books.

system, & any coordinate, P the corresponding force, and N, M specific heats. The usual equations are

deduced by treating de, dm as complete differentials. —Dr. Galt, SOCIETIES AND ACADEMIES

of Glasgow University, communicated a paper on the micro. DUBLIN.

scopical appearances of the grains in the more commonly occur

ring starches. The paper was full of detail, and was illustrated Royal Dublin Society, March 16.-Proi. G. F. Fitzgerald, by numerous original photographs and lantern slides. In a F.R.S., in the chair. —Prof. J. Joly, F.R.S., and Dr. H. H. paper on methods of mapping rainfall, Mr. A. J. Herbertson Dixon read a paper on the distribution of coccoliths and on described a simple graphical method for taking into account the some microscopic organisms found in Dublin and Killiney Bays. varying lengths of periods of observation of rainfall at different Coccoliths have been found by the authors on the Irish coast at parts of the globe. The mean rainfall values were inserted on Sligo, Slyne Head, Dingle, Waterville, and along the coast of the maps in different coloured inks, according to the length of south Co. Dublin, and on the south coast of England at Wey. period of observation. The general trend of the isohyets could mouth. Samples of water from Loch Inver and Portstuart did be attained by comparing similarly coloured means, and the final not afford any examples. Coccoliths were also found in the positions of the lines fixed by the values at the stations with the mud obtained in the Severn and Liffey beds. In the paper are most extended records. The variableness in the length of the also described a new marine Difflugia and organisms from month is allowed for by drawing isohyetal lines, whose actual Killiney Bay resembling Ehrenberg's Pyxidicula and Xanthidia values are the nominal values multiplied by the days in the corfrom the chalk.-A paper by Prof. W. Noel Hartley, F.R.S., responding month, and divided by one-twelfth of a year ex. and Mr. Hugh Ramage was then read by the former, the subject pressed in days. In a second paper, on the normal rainfall being a determination of the wave-lengths of the principal lines of India and the abnormalities in 1896, Mr. Herbertson in the spectrum of gallium, showing their identity with two lines

showed maps on the mean annual and monthly rainfall of India, in the solar spectrum. The authors have found gallium to be a based on the means published in the rainfall data for 1895, and very widely distributed element in the earth, and to be present those in the annual summary for 1896. also in meteoric bodies. It became natural to inquire if it is

Royal Physical Society, March 16.—Mr. B. N. Peach, present in the sun. The wave-lengths of the two principal lines have not previously been determined by a grating spectro.

President, in the chair. — Papers were read by Mr. W. S. Bruce,

of the Jackson.Harmsworth expedition, and Mr. William Eagle graph, and the authors availed themselves of the kind offer of

Clark, on the mammals and birds of Franz Josef Land. Mr. Dr. Adeney to allow them to photograph spectra of gallium with Bruce, who spent fifteen months on Franz Josef Land in 1896-97, the 214 feet radius grating spectrograph in the Physical Labora.

explained that the number of species, exclusive of mammals and tory of the Royal University of Ireland. The two principal birds, he then obtained exceeded that of any previous Arctic exlines were photographed as bright and reversed lines in arc pedition, he having secured 236 against 216 to the credit of the spectra, and as bright lines in the spark spectrum of a solution of gallium chloride. In these and in the oxyhydrogen spectrum number of species known to Franz Josef Land. He had found

United States expedition of 1881-83. He had at least doubled the of gallium compounds the less refrangible line is always stronger ancient reindeer horns, though there were no reindeer at present than the other. The wave-lengths of the two lines, determined

in the Land. Among the specimens he exhibited were the bones by interpolation from adjacent iron lines, are found to be of whales and walruses found on raised beaches with an elevation 4172-215 and 4033-125. In Rowland's map of the solar spec- of from 50 to 80 feet, plainly indicating their great age ; while trum there are two lines probably identical with these, namely:- one specimen-the scapula of a walrus-was found at a height 4172-211. Source : Aluminium. Intensity : 1,

of 336 feet. The chief point of interest in Mr. Clark's part of and 4033-112. Not identified.

the subject, which was restricted to birds, was the finding of It is pointed out that gallium is present in every bauxite and

several new species-Bonaparte's sandpiper, purple sandpiper, shale examined by the authors, and also in metallic aluminium,

and the shore lark. The first mentioned of these, Mr. Clark said, and no doubt the line 4172211 in the spectrum of aluminium is

was not only a new and remarkable addition to the ornis of really a gallium line. From the very close agreement of the

Franz Josef Land, but it was the first authentic example of this wave-lengths, from the relative intensities of the lines as shown

American species that had been obtained in Europe elsewhere above, and from the evidence of the wide distribution of the

than in the British Isles. Another subject of interest in the element, it seems certain that the two gallium lines are identical

paper was the description of a newly-found nesting place of the with the two lines above mentioned in the solar spectrum, and

ivory gull. This was at Cape Mary Harmsworth, on what was there are no other lines so close to these. The evidence is dis

considered to be one of the largest pieces of bare ground in cussed at length in the paper, as also is the effect of the presence

Franz Josef Land. Of the twenty-two species of birds which of elements upon the spectra of other elements.-Prof. J. P.

formed the avifauna of Franz Josef Land, only ten had been O'Reilly read a paper on the occurrence of anatase and brookite

found breeding, though several more undoubtedly nested there, in the quartzites of Shankill, Co. Dublin. He explained that

while several, again, were mere stragglers. the minerals were found in a mass of yellow earth, met with by

PARIS. the quarrymen in 1888, and had only lately been examined. Academy of Sciences, April 4.-M. Wolf in the chair. The peculiarity of the anatase was its approximation in compo- On a doctrinal point in the theory of quadratic forms, by M. sition to the clay or mineral analysed by Eakins as mentioned by de Jonquières. - Contribution to the study of Zeeman's pheno. Dana in his “System of Mineralogy," edition of 1892, p. 716, menon, by MM. Henri Becquerel and H. Deslandres. An while presenting the crystalline form of anatase, thus allowing account of some experiments on the influence of a magnetic of the presumption that the clay analysed by Eakins and called field upon the periods of vibration of the radiations emitted by by him “Xanthitane," was probably the product of decomposi- incandescent vapours.-Movements of the sensitive plant when tion of an anatase having much the same composition as the grown in water, by M. Gaston Bonnier. The author has sucmineral found at Shankill.

ceeded in cultivating Mimosa pudica completely immersed in

00.

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