a; 
mode is followed, and all are arranged stratigraphically, 
without any attempt to show the more interesting develop- 
mental or time-series. Thus, in both cases the most inter- 
> esting and instructive methods of arrangement are 
entirely neglected in favour of systems which are adapted 
solely to facilitate study by specialists, but which are 
_ comparatively unimportant and uninteresting to the 
_ public. Even to this day it does not seem to be realised 
~by curators of museums, that the collections for study and 
those for public exhibition require to be arranged upon 
totally distinct plans; and that the method which is the 
very best in the one case may be, and usually is the very 
worst in the other. ALFRED R. WALLACE 
Geology of the Counties of England and of North and 
South Wals. By W. Jerome Harrison, F.G.S. 
(London: Kelly and Co., 1882.) 
ALL who have had occasion to use the valuable Post 
Office Directories of the English counties published by 
Messrs. Kelly and Co., will have noticed that the imper- 
fect notes on geology contaired in former editions have 
if now been replaced by very accurate and well-written 
; articles on the subject. These notes on the geology of 
% the English counties have been drawn up, evidently with 
much skill and labour, by Mr. W. J. Harrison. In each 
iy- case'the scattered maps and publications of the Geological 
Survey have been very carefully studied, and the various 
¢: memoirs and notices on the geology of each of the coun- 
j ties contained in miscellaneous journals and magazines 
3 faithfully summarised. The result is that the numerous 
readers of those widely diffused publications, the County 
Diréctories, have at hand a reliable sketch of the geology 
of the district in which they live, carefully brought down 
to the date of publication. What is perhaps of still 
greater importance is, that these sketches include refer- 
ences to all the principal works bearing on the subject, 
so that the reader is told where he may find fuller and 
more detailed information upon any point in which he 
may be interested. We can scarcely conceive a method 
by which useful geological information could be more 
Ss widely diffused, or made more easily available for those 
who wish to obtain correct ideas concerning the geology 
of the district in which they live. These sketches of the 
into a volume, and constitute a very useful work of refer- 
ence. We have tested it in many ways, and find that in 
almost every case the latest information, even when pub- 
lished in journals of very restricted circulation, has been 
discovered and made use of. Mr. Harrison’s essays are 
clearly written, and each of them is preceded by a list of 
: the local Natural-History and Scientific Societies, the 
members of which collect information bearing on the 
geology of the county ; of the museums in which rocks and 
: fossils from the county are preserved ; of the publications 
of the Geological Survey bearing on the county ; and of 
such other works as in any way refer to the subject. In 
all cases where he was in doubt Mr. Harrison appears to 
have sought the assistance of competent authorities, the 
result being a work which is exact, and at the same time 
is written in a popular style. There are numerous excel- 
lent woodcuts, most of which appear to be taken by per- 
mission from the publications of the Geological Survey 
and the Geological Society. We can heartily recommend 
this book as a convenient and reliable work of reference. 
University College Course of Practical Exercises in 
Physiology. By J. Burdon Sanderson, M.D., LL.D., 
F.R.S., with the Co-operation of F. J. M. Page, B.Sc., 
F.C.S., W. North, F.C.S., and Aug. Waller, 
M.D. 8vo, pp.75. (London: H. K. Lewis, 1882.) 
TuHIs book is a mulium in parvo. It gives in a most 
condensed and yet most clear and precise form, an 
account of the method of performing the most important 
r experiments in physiology. It will be useful not only to 
Geology of the English Counties have now been collected | 
! 
| disclose on the subject? The shingle of beaches hea 
students, but to practitioners who wish, with a small 
expenditure of time and labour, to become acquainted 
with the present state of our information, and the mo 
important points in physiology, and the exp 
data on which our knowledge rests. The exercises re-_ 
lating to the physiology of muscle and nerve are especially 
worthy of commendation. They make clear to the stu- 
dent the different arrangements of electrical apparatus, 
the comprehension of which is to many an insuperab 
difficulty, not only during their student’s career, but during 
the whole of their lives. The few and simple diagrams in 
the text are just what were wanted to make the experiments — 
readily understood. Half an hour spent with this little 
work will, we think, give to the beginner a better grasp 
of the subject of which it treats than days spent over — 
more elaborate text-books, however good the latter may 
be for advanced students. F 
Mémotres dela Société des Sciences Physiques et Naturelles 
de ean! 2° série, tome iv. 2° cahier. (Bordeaux: 
1881. 
WE draw attention to this number specially for the benefit 
of such as are interested in the early history of arithmetic. 
It contains (pp. 161-194) an able paper by M. Paul 
Tannery (who is known by his previous similar work 
upon the ‘‘ Collection Mathématique” of Pappus in tome 
iil. pp. 351, &c., of these same Mémoires) on “VArith- 
métique des Grecs dans Héron d’Alexandrie.” He goes 
carefully into the question of the authenticity of the 
several so-called Heronian writings, and analyses those 
which he accepts, and concludes with one or two speci- 
mens of the approximate methods employed. We need 
only mention the names of Cantor, Martin, Hultsch, and 
Rodet as being those of the authors whose works and 
statements are discussed. Other papers are: M. Hautreux, 
“ Etudes météorologiques de la Gironde a la Plata”; M. 
Millardet, “ Pourridié et Phylloxera ; étude comparative — 
de ces deux maladies de la vigne”; M. Royer, “ Ré- 
cherches sur le passage du mercure a travers les liquides” ; 
and M. Ponsot, “ De la reconstitution et du greffage des 
vignes.”? From tbis enumeration it will be seen that ~ 
some of the papers are of a very practical character, 
touching the interests of the commonalty. M. Debrun — 
contributes a short note (and illustration), “Sur un — 
nouveau barométre amplificateur.” e 
menti 
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LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions expressed — 
by his correspondents. Neither can he undertake to return, 
or to correspond with the writers of, rejected manuscripts. — 
No notice is taken of anonymous communications. 
[The Editor urgently requests correspondents to keep their letters 
as short as possible. The pressure on his space is so great 
that it is impossible otherwise to ensure the appearance even 
of communications containing interesting and novel facts.) 
Hypothetical High Tides 
I SHOULD like to be allowed to ask two questions on this 
subject : First. Could the vegetable accumulations from which 
the coal has resulted have escaped destruction if, during their 
subsidence, the world was subject to such tides as Mr. Ball 
postulates? It is difflcult to understand how this could be if the 
shales and sandstones which overlie the coal be of marine or 
estuarine origin. Second. What do the Palzozoic conglomerates 
up by 
the tide, having each layer of sand and pebble laid at the slope 
of the beach face, exhibits when cut at right angles to the trend 
of the beach the continuously oblique bedding which represents 
this slope, the vertical heights of the shingle bed thus laid up 
representing the extreme rise and fall of the tide and surges. 
This may be seen in the case of the Lower Eocene shingle in 
Bickley Cutting of the Dover Railway and in the case of the 
| early Glacial shingle in deep pits at Henham and Halesworth in 
| Suffolk. The latter show a tidal rise and fall there of more than 
twenty-five feet, the former not so much. The same structure 
obtains in the case of sandbanks left dry by the tide, and of such 
