220 
NATURE 
[JuLy 6, 1899 
THE LOST VOLUME OF HUTTON’S THEORY 
OF THE EARTH. 
Theory of the Earth, with Proofs and Mlustrations. In 
four parts. By James Hutton, M.D. and F.R.S.E. Vol. 
iii. Edited by Sir Archibald Geikie, D.C.L., F.R.S. 
(Geological Society, Burlington House, 1899.) 
A S we learn from Sir Archibald Geikie in his interest- 
4 ing preface, the history of the later portion of 
James Hutton’s great work on the “Theory of the 
Earth” is a perplexing question. In 1795 the well- 
known two volumes appeared, containing the first and 
second parts, but the title-page bears the words “in four 
parts.” Of those two the first is little more than a re- 
print of the essay on the same subject read to the Royal 
Society of Edinburgh in 1785. The second part, dealing 
with the operation of natural causes on the surface of the 
globe—or dynamical geology, as it is now sometimes 
called—was new matter. These volumes are without 
preface or preliminary sketch, so that no clue is given to 
the plan of the remainder of the work, while the fact 
that Hutton ends his second volume with an elaborate 
summary suggests that he contemplated a pause of some 
duration before issuing the remainder. At his death, in 
1797, the third volume, according to Playfair, was prac- 
tically complete ; and we do not know why his friends did 
not publish it. Perhaps, as Sir A. Geikie suggests, they 
waited for certain illustrations, which Mr. John Clerk, 
Hutton’s great friend, had promised to furnish. Gaps are 
left for these in the text; but, at any rate, Playfair and 
Lord Webb Seymour quote from the manuscript in a paper 
on Glen Tilt, read to the Royal Society of Edinburgh in 
1814. It was then lost sight of—the earlier portion, in- 
cluding three chapters, has vanished ; the other was a 
parting gift from Lord Webb Seymour to Leonard Horner, 
and was presented by him to the Geological Society 
of London in 1856. In its charge it has remained, 
forgotten by most of the Fellows, till Sir Archibald 
Geikie urged its publication on the Council, promising 
to take upon himself the laborious task of editing. 
Needless to say, this has been admirably done. The 
manuscript is printed as though it had followed on the 
preceding volumes. A few small lacunz or matters 
needing explanation are dealt with in explanatory notes, 
which are models of terseness and a great help to the 
reader, who, in addition, has to thank the editor for an 
index, not only to this volume, but also to the two 
others. 
This fragment of a geological classic is well worth 
the cost of publication. Three of its six chapters 
are more or less controversial, and are thus, to some ex- 
tent, obsolete, though it is always interesting to see how 
difficult problems were viewed by the greater intellects in 
the infancy of the science. But the other three chapters, 
descriptive of geological journeys in the Highlands (in- 
cluding the famous examination of Glen Tilt), in the 
Southern Uplands, and in the Isle of Arran, retain their 
vivacity and freshness though a full century has passed 
since they were penned. They also demonstrate Hutton’s 
power as a field geologist, and thus help to refute the 
reproach which has sometimes been levelled at him of 
being a mere speculator. Besides this, they show that 
he could describe accurately and reason profoundly in the 
NO. 1549, VOL. 60] 
ordinary English tongue ; and this is not the least charm 
in days when geological writing is apt to become a con- 
glomerate of scientific jargon unintelligible to all but 
specialists. Fragment though it be, this volume has an 
interest and value all its own, and our best thanks are 
due to both the learned editor and the Council of the 
Geological Society, for “ The Theory of the Earth” is one 
of the chief foundation stones of modern geology. We 
trust that the attention thus drawn to “ Volume iil.” may 
bring about the discovery of the manuscript which is still 
missing. T. G. BONNEY. 
OUR BOOK SHELF. 
Animals in Motion. An Electro-photographic Investiga- 
tion of Consecutive Phases of Progressive Movements. 
By E. Muybridge. Pp. 264 + 1600 half-tone Pictures. 
(London: Chapman and Hall, Ltd., 1899.) 
Mr. MuyYBRIDGE’s book, “Animals in Motion,” with 
its numerous illustrations, offers a most interesting 
study, not only to the physiologist, the man of science, 
and to lovers of animal nature, but also to the artist 
and archeologist. Mr. Muybridge’s attention was first 
directed to the movements of animals in the year 1872, 
while directing photographic surveys of the United States 
Government on the Pacific coast, by a controversy con- 
cerning animal locomotion which was being carried on 
in San Francisco. Mr. Muybridge tells us that accord- 
ing to Plato the same subject was warmly argued by the 
ancient Egyptians. (This statement is not verified by a 
reference, and it is improbable that the point is men- 
tioned by Plato.) Mr. Muybridge determined to settle 
the question whether, in trotting, the horse ever had the 
four feet simultaneously off the ground. By an ingenious 
arrangement of electrically controlled cameras, Mr. 
Muybridge discovered and definitely proved that the 
trotting horse, in certain phases of his movements, has all 
four feet off the ground at the same time. 
Mr. Muybridge became so fascinated with the new 
subject, namely animal locomotion, that he studied and 
photographed the movements of men, women, children, 
lions, tigers, and other animals both wild and domestic, 
and also the flight of birds. His book contains a series 
of most beautiful and interesting pictures, each illustrat- 
ing some feature of movement. Of these, probably the 
most instructive are those of the child crawling (p. 69) 
and the baboon walking (p. 75). The pictures he ob- 
tained show the exact positions of the legs and feet of 
the animals at certain definite times. The other motions 
of the horse, namely the amble, the trot, the canter, the 
gallop, and some more, are carefully analysed by the 
electro-photographic method. In the fourteen series 
pictures of the trot, 2 and 19 (p. 107) show the four feet 
off the ground at the same time; these are the pictures 
which entirely settled the question which fortunately 
started Mr. Muybridge on his excellent work ; the series 
was photographed at Palo Alto in 1879. The series on 
p- 229 of the mule “ Ruth,” bucking and kicking, show 
that the animal adds marked rotation of the hind- 
quarters to movements which, in themselves, must be 
terrible to the rider. In addition to the electro-photo- 
graphic analysis of the movement of animals, the author 
devised an instrument whereby a series of pictures was 
recombined, and by it a life-like picture of a moving 
animal was projected on to a screen. The instrument is 
called the Zodpraxiscope ; it is in a large degree similar 
to the old Phenakistiscope, made by Dubosq of Paris, by 
means of which moving pictures were projected on toa 
screen at the old Polytechnic Institution (‘‘ Play-book of 
Science,” by J. H. Pepper, 1864). From beginning to 
