606 
dangerous pollution of the water in the higher interests 
of the public health. 
The work is a welcome addition to public health 
literature, and it is sure to meet with general appreciation. 
It should appeal to a wide circle of readers, for it is 
written in a manner which presents a most important 
subject in a clear and intelligible light to everyone. 
Nature Study. Realistic Geography. Model based on 
the 6-inch Ordnance Survey. Designed by G. Herbert 
Morrell, M.A, (London: Edward Stanford.) Price 3s. 
THIS is a model of the country round Streatley-on- 
Thames, constructed by cutting out pieces of cardboard 
according to the contour lines and placing them one 
above another in the positions shown by the map. Spare 
pieces of cardboard, on which the contour lines are 
printed, ready for cutting out to make a second model, 
are enclosed in a portfolio along with the first. The 
construction of models of this kind has been carried out 
for some years in a number of schools, both in this 
country and abroad, but the general experience seems to 
be that, like the trigonometrical survey of the school and 
playground, and other similar devices, the time necessary 
to carry them out is too much for the value of the results | 
obtained. The use of Mr. Morrell’s model undoubtedly 
saves some time, inasmuch as the contour lines are 
already traced, but we suspect that the tracing of the 
contour lines is really the most important part of the 
exercise. But anything which assists in familiarising 
British school children with the ideas of contour lines 
and surfaces is to be welcomed ; it is astonishing how 
many children who are familiarly acquainted with iso- 
bars, isothermals and “iso-” lines of all sorts have 
scarcely heard of contour lines, and it is not too much to 
state that the failure to present the conception of a contour 
or “iso-” line as the intersection of a surface with the 
surface of the earth is almost the fundamental defect in 
our teaching of advanced physical geography. Apart 
from its application to the purpose for which it is imme- 
diately intended, Mr. Morrell’s model should be of value 
to teachers for demonstration. 
A Junior Chemistry. 
+ 228. 
25. 6d. 
THE author’s primary object seems to be to enable boys 
to present themselves successfully for the examinations 
in chemistry held in connection with the Oxford and 
Cambridge locals and similar examinations. He recog- 
nises the existence of a better way of teaching his subject 
than the one he adopts, and urges in extenuation of his 
procedure the inadequate provision made for practical 
science in most secondary schools and the small amount 
of time devoted to science in them. Mr. Tyler expresses 
the hope that the book he has written will enable boys 
in ordinary schools “to acquire, as far as possible, a 
scientific knowledge of chemistry,” but he does not seem 
to understand that science is not properly included in 
the curriculum because of the information its study im- 
parts, but rather as a means of developing a habit of 
mind. Unless chemistry is studied experimentally, and 
is made to train the pupil to observe and to reason from 
his observations, it has no right to a place on the school 
time-table. Before the pupil has been set to study the pre- 
paration and properties of a few simple substances, and 
from his own deductions taught to discover the laws of 
chemical combination, Mr. Tyler tries to explain to him 
the atomic theory, Avogadro’s law, compound radicals, 
and other theoretical considerations. Though the 
author understands well enough all the chemistry a boy 
need learn at school, he does not quite appreciate why 
men of science desire such subjects as chemistry to be 
introduced into school work. 
NO. 1720, VOL. 66] 
By E. A. Tyler, B.A. Pp. viii 
(London: Methuen and Co., 1902.) Price 
NATURE 
[OcToBER 16, 1902 
LETTERS TO THE EDITOR. 
[The Editor does not hold himself responsible for opinions ex- 
pressed by his correspondents. Neither can he undertake 
to return, or to correspond with the writers of, rejected 
manuscripts intended for this or any other part of NATURE. 
No notice ts taken of anonymous communications.) 
Finger Print Evidence. 
By the courtesy of authorities in Scotland Yard, I have just 
received duplicates of two enlarged photographs (on slightly 
different scales). These photographs were lately submitted in 
a court of law to prove the identity of a, the mark left on the 
window frame of a house after a burglary had been committed, 
with 4, the impression of the left thumb of H. J., a criminal 
then released and at large, whose finger prints are preserved and 
classified in Scotland Yard. I wished to show the resemblance 
between @ and 4 by the method described in my ‘‘ Decipherment 
of Blurred Finger Prints,” believing that to be the readiest way 
of explaining to a judge and jury the nature of the evidence 
about to be submitted to them. I send the results. The 
questions of the best mode of submitting evidence and of the 
amount of it that is reasonably required to carry conviction 
deserve early consideration, for we may have a great deal of it 
before long. It is as a contribution towards arriving at a con- 
clusion that I send the enclosed. I should say that in the 
above-mentioned book, each pair of impressions was printed in 
triplicate and on a still larger scale than these. One of the three 
was untouched, the second had lines drawn like those in the 
figure, down the axes of the ridges, the third had the lines and 
numbers and nothing else, just as in the figure. The attention 
SY AA wo 
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oe 
PrP oO YH 
cg Go Clas = 
of the judge and jury could be easily directed by counsel to 
whatever pair of corresponding points he might desire, by 
reference to their common numberon the chart. Without some 
such guidance it would be extremely difficult to do so, for 
persons unaccustomed to finger prints are bewildered by the 
maze of their lineations, 
Certain more or less faint lines run across @ that seem to 
have been made with the brush when painting the window 
frame. They seriously interfere with the lineations just above 
No. 5 and to the right of it. No. 5 is itself so far affected by 
them that I do not attach full weight to it as a point of reference. 
But accurate comparison is possible at nine other points, all of 
which are marked, and a close agreement will be found between 
every pair of them as well as in the number of intervening 
ridges. FRANCIS GALTON. 
[The prints have been too much reduced from the tracings I 
sent, to be quite clear. Thus unless a lens be used, No. 2 in & 
will probably be misinterpreted. ] 
Remarkable Fossil Oysters from Syria. 
IN examining a series of more than one hundred specimens 
of Ostrea (Fxogyra) flabellata, Goldfuss, from the Middle 
Cretaceous of Lebanon, I was struck with the marked reproduc- 
tion in the free upper valves of the figures of other shells to 
which the lower valves have been attached. These specimens 
were all collected in the same place, a hill near Bhamdun, 
Mount Lebanon, Syria. They have been freed by weathering 
from a soft marly rock exceedingly rich in fossils. Specimens 
of Ostrea, Plicatula, Pecten and Anomia have the shell well 
preserved. Many others, including species of Cardium, 
Trigonia, Corbula, Isocardia, Cytherea, Leda, Nucula, 
Cerithium, Alaria, Melo, Pterocera, Turritella, Natica and 
others are preserved only as casts. Consequently the shell to 
