« EelmineJätka »
osten deeply so, but is more generally, in my ex- pear-shaped, hence the name ; other varieties are perience, colourless, except as may be modified by ovoid and Alask-shaped ; occasionally this is comthe presence of food, and it usually entirely fills the pressed, and in one well-marked variety the top or shell. The pseudopodia are not, as a rule, numerous, fundus of the shell has one or two pointed, conical rarely more than five or six, and are long, and processes. In some the sand-grains are large, finger-like. It is not every specimen, however, in rough and angular, in others most minute ; while which the pseudopodia can be seen projected, but other forms have the large and small mixed ia when this is the case they will be found to lengthen varying proportions. One common form here has
or shorten, or slowly to move from side to side, its test off colourless chitinoid membrane, with a few almost continuously, while under observation. The widely-scattered sand-grains and diatoms. The mouth of the test is in most cases inferior and pseudopodia are, in this species, finely granular, and terminal. During the past three months I have and in all my specimens free from colour. found numerous individuals of the genus, belonging Fig. 91, the prevailing form here, of chitinoid to three species.
membrane, wit widely-scattered sand-grains and Difflugia pyriformis is perhaps the commonest diatoms. Empty. Fig. 92, another similar one, species of the genus, and varies greatly in size and with sarcode encysted in a brownish ball. Fig. 93 shape. The typical form is narrowly or broadly | large form, [test composed entirely of sand-grains.
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 de. 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 išo 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.
Pseudopodia extended. Fig. 94, very fine specimen from Sphagnum ; test of extra large and rough sand-grains. Size o 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. Size from bo to ado of an inch.
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 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 i 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 is to išo 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
NOTES ON NEW BOOKS.
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
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 bas converted into bread- -no fewer than 623,000 tons of basic slag. This wonderful success in metallurgy was due almost solely to the patience and 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 Thanies Police Court. Within the brief period of a twelvemonth we find him a.
clerk, and then the acknowledged leading metallur- Trees, by A. S. Packard (Washington : Government gist of his day. It is a wonderful story of what a Office). This is a neatly got-up volume of a thousand young man can do, and Mr. Burnie has told it well pages, illustrated by forty plates, and upwards of in this handsome volume.
three hundred woodcuts. The papers are strictly Coal, and what we get from it, by Professor R. scientific and thoroughly practical. Hence their Meldola (London : S.P.C.K.). This is perhaps the high economic value. They deal with the various most interesting of the volumes yet issued under insects injurious to the oak, elm, hickory, butter-nut, the title of “The Romance of Science." It is locust-tree, maple, cotton-wood, poplar, lime, birch, a much-expanded issue of a Lecture delivered by beech, wild cherry, wild plum, thorn, crab-apple, Professor Meldola at the London Institution, and mountain ash, willow, hackberry, sycamore, pine, both to the student and the general reader it is a spruce, fir, hemlock, larch, juniper, cedar, cypress, highly-valuable, clear, and concise account of the &c., with full descriptions of the habits of their now-important coal-tar industry. All the valuable insect enemies, and advice how to cope with them. materials here explained not many years ago were Annual Report of the Fruit-Growing Association worse than wasted. Science has reduced them, and and Entomological Society of Ontario, 1890 (Toronto). turned them to use. About three hundred coal-tar This volume is the twenty-second annual report of colouring-matters are now made, and thirty of these a most useful society. It is full of capital practical are in economic use, all of them fast dyes. There papers on many matters concerning peaches, pears, are thirty more fast enough for all practical require- prunes, cherries, apples, grapes, &c., their growth, ments. The value of the coal-tar colouring-matters decay, enemies (animal and vegetable). Horticul. annually produced in Great Britain and on the turists all over the world will be interested in this Continent is five millions sterling. From the same useful volume, which it is a great pity to have original source are also derived such explosives as spoiled by the wretched photograph of the President picric acid, medicines such as antypyrin, sweets as frontispiece. such as saccharin, and perfumes resembling vanilla, Zoological Articles contributed to the “Encyclobitter almonds, &c., to say nothing of the hydro- pædia Britannica,” by Professor E. Ray Lankester, quinin and eikeneogen used by photographers and &c. (London: A. & C. Black). All earnest students others. Professor Meldola's book is a genuine of advanced zoology are already aware that the last “Romance,” far transcending in interest and plot edition of the “Encyclopædia Britannica” contains three-fourths of the so-called “ novels” of the day. some of the most exhaustive articles on special
It is a book that will be largely read and highly- subjects connected with their science which have yet prized.
been published. They are not likely to be excelled Colour Measurement and Mixture, by Captain for some time to come, and that ponderous but usesul Abney (London: S.P.C.K.). This is another of the work would therefore have had to be consulted, the same half-crown series—all of which are written papers picked out of its many volumes, and much iby the chief recognised authorities on each subject. time have been lost, if Professor Lankester and the Whatever Captain Abney has to say on the matters publishers had not hit upon the happy thought of There discussed is sure to be listened to.
issuing the present volume at such a price that it few appeals from his conclusions, especially when they comes within pocketable reach of most students, concern the physics and chemistry of photography,
and lies in such a handy and compact form, Students will here find worked-out the heating, both for careful study and reference, that few luminous, and chemical effects of the spectrum.
naturalists or general libraries can do without it. The work contains sixteen chapters, devoted largely
The illustrations are numerous, and one or two to colours, their origin, effects, combinations, &c., important additions have been made to them over and is abundantly illustrated where necessary to a
and above those in the original work. The text, fuller understanding of the text.
also, has been corrected and slightly added to where The Missouri Botanic Garden. This institution necessary and convenient.
On the various papers was founded by the late Mr. Henry Shaw, of whom themselves it is not necessary to make any remarks. .a lengthy biographical sketch is given. Professor Their high-class character practically places them Trelease's “Inaugural Address," and a
beyond the reach of criticism. All Professor Sermon,” together with the First Annual Report, are Lankester's articles are here reprinted-on “ Protoincluded in this nicely got-up volume. It is well zoa, Hydrozoa, Mollusca, Polyzoa, and Vertebrata.” illustrated. Mr. Shaw must have been a very
In addition we have the following papers, by sociable fellow, for he left money for an annual permission of the authors—“Sponges,” by Professor banquet. Accordingly we have the report of that
“Planarians," by Professor von Graff: also, at which banquet one hundred guests were “Nemertines,” by Professor Hubrecht; “Rotifera," present.
by Professor Bourne; and on “ Tunicata," by Fifth Report of the United States Entomological Professor Herdmann. Commission on Insects injurious to Forest and Shade Telescopic Work for Starlight Evenings, by
that England was united with the
W. F. Denning (London: Taylor and Francis). Thou, like blue litmus in the acid test, Astronomical students and amateurs of the science Whene'er we met, wouldst turn to rosy red, are numerous, and they are not unprovided with And when my love undying I confessed, manuals and other guides. But we doubt if we Thy words were sweet as acetate of lead ; possess any which so fully meets their wants as the Now truly are they changed to vitriol instead. book before us. Its author is an enthusiastic amateur astronomer, who has contributed for many
For, turning to analysis improper, years past much valuable original work to the science
A quantitative test was made for gold, to which he is devoted. A completer working manual
And when but little else there seemed than copper of astronomy than this, his last-issued work, it is
And scanty silver in the cash I hold, difficult to conceive. It is full, clear, accurate, and
Thy love grew straightway like a freezing-mixture yet popular. Many of the chapters have appeared
cold. as special papers contributed to scientific magazines,
Entirely siliceous was thy heart; where soine of our readers must have met with
Thy love was gone. The sequel need I tell ? them. The chapters are as follows :—“The Tele
Betrothed unto another now thou art, scope, its Invention, and the Development of its
Like to the atom H we know so well, Powers,” “Relative Merits of Small and Large
Which leaves its own 0, to join the base CI ! Telescopes,” “Notes on Telescopes and their
A. C. DEANE. Accessories,” “Notes on Telescopic Work,” “ The
""The Moon,” “Mercury,” “Venus," "Mars,” "The Planetoids," " Jupiter,” “Saturn,” “ Uranus
THE GEOLOGICAL HISTORY OF THE and Neptune," "Comets and Comet-Seeking,"
THAMES VALLEY. “Meteors and Meteoric Observations,” “ The Stars,” "Nebulæ and Clusters of Stars," &c. The illustra. By Dr. A. IRVING, F.G.S., &c., Wellington Coll. tions are sixty-four in number, and all are of a
[Continued from p. 112.) high-class character. Paper, type, and binding alto
THE GLACIAL PERIOD AND SINCE. gether make up a handsome and pleasant-looking volume.
'HE Geologists' Association-A Record of Excursions continent of Europe during Miocene, Pliocene, made between 1860 and 1890, edited by T. V. Holmes and Quaternary times, has long been recognised by and C. D. Sherborn (London : Ed. Stanford). We some of our leading geologists. The sea not having have frequently thought, when we have received the cut its way as yet through the Quaternary isthmus to pithily explained and well-illustrated pamphlets sent
form the present Strait of Dover, the great glaciers. out to members describing the places to be visited
of Scandinavia on the one hand, and of Northern at each excursion, what a pity it was they were not Britain on the other, seem to have formed by their collected in a more permanent form. Each account confluence a mighty dam, which ponded back the is written by a local specialist, and each diagram and waters of a vast drainage-area of Central Europe and illustration is the most interesting in the district. Southern Britain. This, at least, from a consideraAll; England and Wales have thus been visited by
tion of all the evidence on the one side and on the members of the Geologists' Association during the other, would appear to have been a most important last thirty years.
Therefore we are unexpectedly factor in the glaciation of Central and Southern pleased to welcome the present volume, which is just England. The facts inductively arrived at have the very thing we have so long thought ought to be been well represented by the late Professor Carvill done. By its very nature, it must be the very best Lewis of Philadelphia, on a map, which was printed field-manual of British geology yet issued. Between for Section C of the British Association, when it met two and three thousand places are referred to in the at Manchester in 1887. The moraines have been index, and there are 214 maps and sections. Every taken as indications of the boundary of the great student of field-geology should forthwith procure this northern ice-sheet; and the extra-morainic lake, useful work, which has been excellently edited by
which then covered most of the Midland and Messrs. T. V. Holmes and C. D. Sherborn.
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, A SCIENTIFIC PLAINT.
by the ice which floated down this narrow channel to LAS, those happy days which we have seen widen and deepen it. Professor Prestwich* assigns
When thou, whose fickleness I now deplore a deepening of the gorge to the extent of some 220 Wert like to concentrated saccharine ;
feet to glacial action. This is probably an excessive Those happy days can come to us no more, When ardent love is strong as H, SO,
• " Journal Geol. Soc.," \ol. xlvi., p. 149.
• estimate, for two reasons. (1) The plateau-gravels, is maintained in a most remarkable manner through which cap the adjacent hills, and which he assigns the contortions of the strata. Examples may be seen (as equivalents in time of his Mundesley and Westleton in the railway-cuttings at Wokingham and SunningBeds) to the beginning of the Quaternary period, hill, on the South-Western Railway ; but the finest may be merely terrestrial deposits of the Pliocene by far have been lately brought to light in the Mercian river-system, and more nearly equivalent in excavations in the brick-yard of Messrs. T. Lawrence time to the plateau-gravels of Berks and West & Sons, close to the Nine-mile Ride in Old Windsor Surrey, being certainly older than the present Chalk Forest.* Some of the best of these are gone for escarpment; (2) the extent to which the gorge has ever, as the pits have been extended; but, fortusince been cut down to its present level, appears, nately for science, photographs were secured by drom still more recently-published observations to be members of the photographic section which has been greater than he has estimated.* We may, perhaps, recently started by the Natural History Society of deduct 100 feet at least from his estimated 220 Wellington College. One of them, it is hoped,
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 remark. able 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, f into the clays, the lamination of which
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
* See reference below to Mr. Shrubsole's paper.
* A suggestion of Dr. J. W. Spencer, the State Geologist of Georgia, when on a visit to the author last year.