170 
NATURE 
[ DECEMBER 24, 1896 
It may be said generally that any one mastering the 
work would have a very competent knowledge of the 
subject, and one which he could not obtain from any 
other single source. 
To summarise, it must be allowed (1) that a text-book 
upon petroleum—at once comprehensive and authori- 
tative—was greatly needed; (2) that there was hardly 
any one capable of compiling such a work; (3) that Mr. 
Redwood has most successfully essayed and accomplished 
the task by the production of this most excellent text- 
book. 
Unlike Mr. Redwood’s work, that of Prof. Jaccard is 
concerned solely with the geology of petroleum, though 
the geology is of that wide order that it embraces such 
subjects as the origin of petroleum and of natural gas, 
and the causes of “ bituminisation.” 
The study of the various conditions under which 
petroleum occurs in nature, is remarkably clearly written 
and is, moreover, illustrated by many admirable little 
semi-diagrams, thoroughly French in character, and 
truly luminous to the text: the work is, however, 
marred by the narrowness of view, displayed in the 
selection of the sources drawn upon, by the not infrequent 
antiquity of these latter, and by the only too obvious 
circumstance that for many of the localities, whose 
petroliferous peculiarities are described, the author only 
knew the facts at second-hand. Thus the account given 
of the occurrence of Galician petroleum and of the 
industry founded thereupon, is ridiculously brief; its 
inaccuracies at once stultifying also the author’s table 
showing the occurrence of petroleum in strata of various 
ages. Transylvanian petroleum, including the interesting 
deposits about Soosmezo, is, apparently, not even 
mentioned, while the Roumanian deposits, much less 
important than those of Austria-Hungary, are described 
at some length—or, rather, M. Coquand’s reports upon 
them are abstracted at some length. From the above 
it will be gathered that that study so much needed at 
the present moment, viz. a critical comparison of the 
petroliferous rocks of the Carpathians, has not been 
attempted by the author. 
Naturally, when treating of the Jura, Vosges, Hano- 
verian, &c., petroleum localities, subjects to which he has 
devoted individual attention, Prof. Jaccard speaks with 
unquestionable authority, and this is the most valuable 
part of the book. 
The author seems to have attempted to put forth his 
greatest strength in the chapters dealing with the origin 
of petroleum and its conditions of occurrence in the 
rocks, and the causes of these conditions. Though he 
admits a vegetable origin for certain petroleums, he 
considers, largely influenced to this opinion by his 
studies of the fossils of the Jura deposits, that a bitu- 
minisation of certain animal (especially molluscan) 
remains may be fairly demonstrated. 
In spite of the fact that the work of French geologists 
is too exclusively referred to, while the work of others is 
often ignored, yet the book is an eminently clear and 
readable one ; and, regard being had to the existing 
works, treating of the geology of petroleum, an English 
translation would undoubtedly be useful at the present 
time. 
It may be noted that, prefixed to the work, there is an 
NO. 1417, VOL. 55] 
account of the life and work of Prof. Jaccard (died 
January 5, 1895). 
In Mr. Boyd’s readable book of eighty-five short pages 
a well-known petroleum-expert glances rapidly over the 
whole range of the subject for the benefit, primarily, of 
those who wish to glean some smattering of petroleum- 
lore. The subject is one which is attracting in- 
creased attention from the general public, and this 
booklet will no doubt be found useful by a large class 
of readers. It isa pleasure to be able to add that the 
information contained in it is equally trustworthy within 
the scope contemplated, and entertaining, because well 
arranged and clearly explained. 
The work would be still more attractive, and its sphere 
of usefulness enlarged, if in another edition there were to 
be added to it two or three sketch maps and an 
illustration of a drilling plant. By RB: 
THE AIM OF BIOLOGICAL TEACHING. 
Biological Lectures Delivered at the Marine Biological 
Laboratory at Woods Holl, in the Summer Session 
of 1895. Pp. 188. (Boston, U.S.A., and London: Ginn 
and Co., 1896.) 
“ 7T TRUST that you all, when you leave the laboratory, 
will carry with you a deeper and loftier enthusiasm 
for original research, which is at once the chief duty and 
the chief privilege of the biologist.” Thus Prof. Minot 
concludes the discourse which he has contributed to this 
volume ; and the sentence not only serves to illustrate the 
object of the lectures themselves, but at the same time 
expresses the ideal of that movement in biological teach- 
ing of which the lectures are a sign. It is to the credit 
of American teachers of natural science, and more 
especially of the teachers of biology, that they, more 
faithfully and successfully than their fellow-workers in 
this country, have striven to keep in view the true end 
and aim of all scientific teaching—a training in that 
method, whose ultimate goal is the increase of knowledge 
by means of scientific research. 
The lectures now brought together in volume form were 
delivered, as the title states, at the Marine Biological 
Laboratory of Wood’s Holl, in the summer session of 
1895. At the laboratory there are assembled during the 
summer months a considerable number of naturalists 
engaged in biological research, together with a large 
body of university students, who have not yet completed 
their biological course, and the excellent practice has 
been instituted of inviting the investigators to deliver 
lectures upon their work for the benefit both of their 
colleagues and of the students. 
To students who have been taught to regard scientific 
research as the end towards which all their studies are 
directed, nothing could be more stimulating, especially 
at a time when they are brought into such intimate 
contact with nature, as a residence at a marine laboratory 
affords, than lectures such as these, delivered by men 
who are themselves actually working at the subjects 
about which they speak. Yet we cannot refrain from 
remarking, what no one who has been brought into 
contact with English students with the dead hand of 
the examination hanging over them will deny, that for 
the latter such discourses would possess but little interest. 
