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Pseudopodia extended. Fig. 94, very fine specimen from Sphagnum; test of extra large and rough sand-grains. Size of an inch. Difflugia globulosa is another common form, one of the smallest of the genus. It was one of the first to be described and figured, and is probably the D. proteiformis of the illustrious Ehrenberg. Its general form is that of a round or oval box, more or less truncated at the mouth. One common variety has exactly the form of the box' of the sea urchin (Echinus). In the character of the materials used in the formation of the test, and in other particulars, it differs little from the preceding. I occasionally come across a form in several of our shaded wells and clear pools, which has a large, eccentric mouth, like D. constricta, or the spineless form of Contropyxa aculeata. As it is too low for the former, and is wanting in the appendages to the incurved mouth of the latter, it more properly, I think, may be placed here. from too of an inch.

Size

Fig. 95. Empty test, made up of minute sandgrains; ventral view.

Fig. 96 of chitinoid membrane, with scattered large sand-grains. Side view, pseudopodia extended.

Fig. 97. This form might, with almost equal propriety, be classed with D. constricta, or even with Centropyxis ecornis, as the mouth is eccentric, and the highest part of the shell behind the mouth; but it appears to me, for reasons given above, to have a greater affinity to the present species.

Fig. 98. Side view of specimen with closelypacked sand-grains. Fig. 99.

The same, rolled over to show the mouth of the shell.

Difflugia acuminata is also an equally common form here, and I procure it in considerable numbers from among Sphagnum in boggy places, and in most of our shady wells and clear pools. The prevailing form is shown in Fig. 100. The species may be described as pyriformis, drawn out to a point at the top (fundus).

The test is oblong oval, in the typical form, narrowing towards the mouth, and more or less suddenly tapering towards the summit, in varying degrees of acuteness. Although this species is as variable as any in the genus, I have only as yet found two well-marked varieties, during the three months I have been specially studying the Rhizopods. Like the preceding species, the test is made up of sand-grains, occasionally intermixed with the frustules of diatoms, or it is obviously of chitinous membrane, either colourless or yellow, more or less incrusted with the above elements, sometimes very irregularly so. Size from too of an inch. Sarcode rarely coloured.

Fig. 100. The prevailing form in this district, of colourless chitinoid membrane, with scattered sandgrains and diatoms. Pseudopodia extended.

Fig. 101. Large specimen, from shaded well, test

of yellow, wrinkled chitine, with large sand-grains and a few linear diatoms. The sand and diatoms do not project much, but are apparently sunk in the membrane, and so partake of its yellow colour. In my next I shall treat of the box-like Centropyxis, and the genus Arcella. The latter is one of the commonest forms of the Rhizopods, and is the one most frequently noticed by microscopists who do not make a special study of the class.

Difflugia urceolata is a large variable form closely related to D. acuminata. The shell is somewhat ovate, amphora-like; fundus either evenly rounded or more or less acute, frequently furnished with blunt spines. Neck short; mouth large and round, occasionally with a reflected rim.

This handsome species is of rare occurrence in this district, and when I do find a specimen it has generally been an isolated one. My specimen has an acute fundus, and the neck is only slightly reflected. Size about inch. The test is of sand grains—a few large ones, regularly distributed, the intervals filled up with smaller ones of nearly equal size (Fig. 104). J. E. LORD.

Rawtenstall.

NOTES ON NEW BOOKS.

MEMO

EMOIR OF SIDNEY GILCHRIST THOMAS, by R. W. Burnie (London: John Murray). This is altogether a noble, bright, and cheerful book-the pleasant record of a brilliant

young life. The "Thoman-Gilchrist process, by

which formerly half-worthless iron ore is converted into good stuff, by having its phosphorus extracted, whilst the latter in its turn is utilised as artificial manureis already well-known to most of our readers. Only thirteen years ago there was not in existence any public record of the successful dephosphorisation of pig-iron-last year there were 2,603,083 tons produced. In addition, last year there were placed on the market, to be used as artificial manure-stones. that science has converted into bread-no fewer than 623,000 tons of basic slag. This wonderful success. in metallurgy was due almost solely to the patienceand unwearying industry of Sidney Gilchrist Thomas, and yet he died (of overwork, it is to be feared) at the early age of thirty-four. By that time he had come to be acknowledged as the most brilliant metallurgist of the century. Honours from all countries were showered thickly upon him. And yet this scientist left school at seventeen to be a schoolteacher. At eighteen he was clerk in a London Police Court, an office he held for twelve years. He studied chemistry, mineralogy, geology, &c., on. what leisure evenings he had, and conducted his experiments and investigations then and during his holidays. He made his valuable discovery whilst still a clerk at the Thamies Police Court. Within the brief period of a twelvemonth we find him a.

clerk, and then the acknowledged leading metallurgist of his day. It is a wonderful story of what a young man can do, and Mr. Burnie has told it well in this handsome volume.

Coal, and what we get from it, by Professor R. Meldola (London: S.P.C.K.). This is perhaps the most interesting of the volumes yet issued under the title of "The Romance of Science." It is a much-expanded issue of a Lecture delivered by Professor Meldola at the London Institution, and both to the student and the general reader it is a highly-valuable, clear, and concise account of the now-important coal-tar industry. All the valuable materials here explained not many years ago were worse than wasted. Science has reduced them, and turned them to use. About three hundred coal-tar colouring-matters are now made, and thirty of these are in economic use, all of them fast dyes. There are thirty more fast enough for all practical requirements. The value of the coal-tar colouring-matters annually produced in Great Britain and on the Continent is five millions sterling. From the same original source are also derived such explosives as picric acid, medicines such as antypyrin, sweets such as saccharin, and perfumes resembling vanilla, bitter almonds, &c., to say nothing of the hydroquinin and eikeneogen used by photographers and others. Professor Meldola's book is a genuine "Romance," far transcending in interest and plot three-fourths of the so-called "novels" of the day. It is a book that will be largely read and highlyprized.

Colour Measurement and Mixture, by Captain Abney (London: S.P.C.K.). This is another of the same half-crown series-all of which are written by the chief recognised authorities on each subject. Whatever Captain Abney has to say on the matters there discussed is sure to be listened to. There are few appeals from his conclusions, especially when they concern the physics and chemistry of photography. Students will here find worked-out the heating, luminous, and chemical effects of the spectrum. The work contains sixteen chapters, devoted largely to colours, their origin, effects, combinations, &c., and is abundantly illustrated where necessary to a fuller understanding of the text.

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The Missouri Botanic Garden. This institution was founded by the late Mr. Henry Shaw, of whom a lengthy biographical sketch is given. Professor Trelease's "Inaugural Address," and a "Flower Sermon," together with the First Annual Report, are included in this nicely got-up volume. It is well illustrated. Mr. Shaw must have been a very sociable fellow, for he left money for an annual banquet. Accordingly we have the report of that also, at which banquet one hundred guests were present.

Fifth Report of the United States Entomological Commission on Insects injurious to Forest and Shade

Trees, by A. S. Packard (Washington: Government Office). This is a neatly got-up volume of a thousand pages, illustrated by forty plates, and upwards of three hundred woodcuts. The papers are strictly scientific and thoroughly practical. Hence their high economic value. They deal with the various insects injurious to the oak, elm, hickory, butter-nut, locust-tree, maple, cotton-wood, poplar, lime, birch, beech, wild cherry, wild plum, thorn, crab-apple, mountain ash, willow, hackberry, sycamore, pine, spruce, fir, hemlock, larch, juniper, cedar, cypress, &c., with full. descriptions of the habits of their insect enemies, and advice how to cope with them.

Annual Report of the Fruit-Growing Association and Entomological Society of Ontario, 1890 (Toronto). This volume is the twenty-second annual report of a most useful society. It is full of capital practical papers on many matters concerning peaches, pears, prunes, cherries, apples, grapes, &c., their growth, decay, enemies (animal and vegetable). Horticulturists all over the world will be interested in this useful volume, which it is a great pity to have spoiled by the wretched photograph of the President as frontispiece.

Zoological Articles contributed to the "Encyclopædia Britannica," by Professor E. Ray Lankester, &c. (London: A. & C. Black). All earnest students of advanced zoology are already aware that the last edition of the "Encyclopædia Britannica" contains some of the most exhaustive articles on special subjects connected with their science which have yet been published. They are not likely to be excelled for some time to come, and that ponderous but useful work would therefore have had to be consulted, the papers picked out of its many volumes, and much time have been lost, if Professor Lankester and the publishers had not hit upon the happy thought of issuing the present volume at such a price that it comes within pocketable reach of most students, and lies in such a handy and compact form, both for careful study and reference, that few naturalists or general libraries can do without it. The illustrations are numerous, and one or two important additions have been made to them over and above those in the original work. The text, also, has been corrected and slightly added to where necessary and convenient. On the various papers themselves it is not necessary to make any remarks. Their high-class character practically places them beyond the reach of criticism. All Professor Lankester's articles are here reprinted-on "Protozoa, Hydrozoa, Mollusca, Polyzoa, and Vertebrata." In addition we have the following papers, by permission of the authors-" Sponges," by Professor Sollas; Graff: "Planarians," by Professor von "Nemertines," by Professor Hubrecht; "Rotifera," by Professor Bourne; and on "Tunicata," by Professor Herdmann.

Telescopic Work for Starlight Evenings, by

W. F. Denning (London: Taylor and Francis). Astronomical students and amateurs of the science are numerous, and they are not unprovided with manuals and other guides. But we doubt if we possess any which so fully meets their wants as the book before us. Its author is an enthusiastic amateur astronomer, who has contributed for many years past much valuable original work to the science to which he is devoted. A completer working manual of astronomy than this, his last-issued work, it is difficult to conceive. It is full, clear, accurate, and yet popular. Many of the chapters have appeared as special papers contributed to scientific magazines, where some of our readers must have met with them. The chapters are as follows:-"The Telescope, its Invention, and the Development of its Powers," "Relative Merits of Small and Large Telescopes," "Notes on Telescopes and their Accessories," "Notes on Telescopic Work," "The Sun," ,""The Moon," "Mercury,' 19 66 99.66 Venus, 'Mars," "The Planetoids," " "Jupiter," "Saturn," 66 Uranus and Neptune," "Comets and Comet-Seeking," "Meteors and Meteoric Observations," "The Stars," "Nebula and Clusters of Stars," &c. The illustrations are sixty-four in number, and all are of a high-class character. Paper, type, and binding altogether make up a handsome and pleasant-looking volume.

Geologists' Association-A Record of Excursions made between 1860 and 1890, edited by T. V. Holmes and C. D. Sherborn (London: Ed. Stanford). We have frequently thought, when we have received the pithily explained and well-illustrated pamphlets sent out to members describing the places to be visited at each excursion, what a pity it was they were not collected in a more permanent form. Each account is written by a local specialist, and each diagram and illustration is the most interesting in the district. All: England and Wales have thus been visited by members of the Geologists' Association during the last thirty years.

Therefore we are unexpectedly pleased to welcome the present volume, which is just the very thing we have so long thought ought to be done. By its very nature, it must be the very best field-manual of British geology yet issued. Between two and three thousand places are referred to in the index, and there are 214 maps and sections. Every student of field-geology should forthwith procure this useful work, which has been excellently edited by Messrs. T. V. Holmes and C. D. Sherborn.

A SCIENTIFIC PLAINT.

ALAS, those happy days which we have seen

When thou, whose fickleness I now deplore Wert like to concentrated saccharine;

Those happy days can come to us no more, When ardent love is strong as H, SO..

Thou, like blue litmus in the acid test,
Whene'er we met, wouldst turn to rosy red,
And when my love undying I confessed,

Thy words were sweet as acetate of lead;
Now truly are they changed to vitriol instead.
For, turning to analysis improper,

A quantitative test was made for gold, And when but little else there seemed than copper And scanty silver in the cash I hold,

Thy love grew straightway like a freezing-mixture cold.

Entirely siliceous was thy heart;

Thy love was gone. The sequel need I tell? Betrothed unto another now thou art,

Like to the atom H we know so well, Which leaves its own O, to join the base Cl! A. C. DEANE.

THE GEOLOGICAL HISTORY OF THE
THAMES VALLEY.

By Dr. A. IRVING, F.G.S., &c., Wellington Coll. [Continued from p. 112.]

THE GLACIAL PERIOD AND SINCE.

THE probability that England was united with the

continent of Europe during Miocene, Pliocene, and Quaternary times, has long been recognised by some of our leading geologists. The sea not having. cut its way as yet through the Quaternary isthmus to form the present Strait of Dover, the great glaciers of Scandinavia on the one hand, and of Northern Britain on the other, seem to have formed by their confluence a mighty dam, which ponded back the waters of a vast drainage-area of Central Europe and Southern Britain. This, at least, from a consideration of all the evidence on the one side and on the other, would appear to have been a most important factor in the glaciation of Central and Southern England. The facts inductively arrived at have been well represented by the late Professor Carvill Lewis of Philadelphia, on a map, which was printed for Section C of the British Association, when it met at Manchester in 1887. The moraines have been taken as indications of the boundary of the great northern ice-sheet; and the extra-morainic lake, which then covered most of the Midland and Eastern Counties, overflowed by the Upper Avon line of drainage into the Severn Valley, and by the Oxford Basin and the Pangbourne Gap into the Thames Valley. Much work was done, no doubt, by the ice which floated down this narrow channel to widen and deepen it. Professor Prestwich* assigns a deepening of the gorge to the extent of some 220 feet to glacial action. This is probably an excessive

"Journal Geol. Soc.," vol. xlvi., p. 149.

estimate, for two reasons. (1) The plateau-gravels, which cap the adjacent hills, and which he assigns (as equivalents in time of his Mundesley and Westleton Beds) to the beginning of the Quaternary period, may be merely terrestrial deposits of the Pliocene Mercian river-system, and more nearly equivalent in time to the plateau-gravels of Berks and West Surrey, being certainly older than the present Chalk escarpment; (2) the extent to which the gorge has since been cut down to its present level, appears, from still more recently-published observations to be greater than he has estimated.* We may, perhaps, deduct 100 feet at least from his estimated 220

is maintained in a most remarkable manner through the contortions of the strata. Examples may be seen in the railway-cuttings at Wokingham and Sunninghill, on the South-Western Railway; but the finest by far have been lately brought to light in the excavations in the brick-yard of Messrs. T. Lawrence & Sons, close to the Nine-mile Ride in Old Windsor Forest.* Some of the best of these are gone for ever, as the pits have been extended; but, fortunately for science, photographs were secured by members of the photographic section which has been recently started by the Natural History Society of Wellington College. One of them, it is hoped,

[graphic]

Fig. 106.-Section of Glaciated Clays and Gravel at Easthampstead, Berks, in Old Windsor Forest (March, 1891).

feet, as the vertical measurement of the work of erosion during the Glacial Period.

Professor Carvill Lewis estimated that the waters of the above-named extra-morainic lake stood some 250 feet above the present sea-level in the old Thames Straits of the Glacial Period. Now it is a remarkable fact that at very near this elevation-that is to say, at levels varying from 220 to 240 feet-the author has, within the last year or two, made a considerable number of observations of glacial action in East Berks. The laminated clays are highly contorted, and great masses of sand and gravel, weighing in some cases many tons apiece, have been driven bodily, in a solid (frozen) state, † into the clays, the lamination of which

* See reference below to Mr. Shrubsole's paper.
† See "Journal of the Geol. Soc.," vol. xlvi., p. 561.

will be reproduced for publication by the Geologists' Association of London. Subjoined is a later photograph of a section, now also obliterated, and only exposed to open daylight for a few days in March, 1891. (See Fig. 106.) It was taken by one of the author's pupils, Mr. McClintock, of Wellington College. Copies of the earlier photographs were exhibited at the lecture, and some of them have found their way to the Woodwardian Museum at Cambridge, and to the British Association. A little reflection will show that these marks of ancient glaciation, probably the work of pack-ice, as it was drifted and stranded by high winds on the margin of the old Thames Straits, may be taken as a

A suggestion of Dr. J. W. Spencer, the State Geologist of Georgia, when on a visit to the author last year.

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