550 
NATURE 
[OcToBER 5, 1899 
‘has set himself to this study, and his results are published as a 
monograph—‘‘ The Accuracy of Voluntary Movement ”—in 
The Psychological Review (vol. iii. 1899). The following are 
‘some of his conclusions ; When the eyes are used, the accuracy 
of a movement diminishes as the speed increases; but it does 
not vary so much when the eyes are not used; the right hand 
is slightly more accurate than the left. When the interval 
between successive movements is kept constant and the speed 
of the motion alone varied, the accuracy diminishes rapidly as 
the speed increases, the accuracy also diminishes on keeping 
the speed constant and varying the interval alone; the accuracy 
-of initial adjustment is favoured by a short interval, accuracy 
of current control by a low speed ; fatigue increases the vari- 
ability of a performance, but practice decreases it, variability 
means improvability. Finally, the author advocates a new 
mode of writing, as he finds that the side to,side movement of 
the wrist and forearm possesses advantages in point of ease and 
of speed over the usual thumb-and-finger movement, or a 
movement of the whole arm from the shoulder. 
Dr. MArrIo BARatTTa has contributed a preliminary sketch 
of his work on the Latian earthquakes to the Rivista Marittima 
for August. He shows that the more important shocks are 
‘connected with certain definite seismic centres, the positions of 
which he determines. An interesting comparison is made 
‘between the earthquakes of an extinct volcanic region, such as 
the Alban Hills, and those which precede, accompany and 
follow an eruption of an active volcano such as Etna. In both, 
the disturbed areas are as a rule extremely small, and yet near 
their centres the shocks may be strong enough to damage 
‘buildings. Also, in successive shocks, there are many changes 
in the positions of the epicentral areas. 
M. A. DE GRAMONT sends a reprint of an article de- 
scribing a method he has devised tor varying the scale and 
dispersion of a laboratory spectroscope (Comptes rendus, vol. 
exxviii., p. 1564, June 1899). The scale is adapted in the usual 
way by placing it at the end of a collimator tube and arranging 
that the light from the scale shall be reflected from one face of 
the prism into the observing telescope; but instead of having 
only one lens in the scale tube, fixed at its principal focus from 
the scale, there are two lenses there, whose distances from each 
other and from the scale can be varied by known amounts. It 
will be at once apparent that the effect of this will be to alter 
the magnification of the scale as seen in the observing telescope, 
and in practice the scale is so altered that a certain number of 
divisions always correspond to the distances between the same 
two spectrum lines, whatever kind of prism or dispersive 
arrangement is being used. The variation in the dispersion is 
obtained in a well-known but little used manner, by rotating the 
prism about its refracting edge, and using positions more or less 
removed from that of minimum deviation, the dispersion being 
increased or decreased accordingly as the prism is turned 
towards the collimator or telescope from the mean position. A 
useful diagram is given bringing together the various effects on 
the dispersion by gradual displacements of the prism. The 
author is investigating more closely the variation of dispersion 
with the angle of incidence, and will communicate results later. 
AN observation of some interest in connection with recent 
discussions on heredity is recorded by M. Casimir de Candolle 
in a paper read before the Socé#é de physique et a histoire 
naturelle de Geneve. He points out a constant difference 
between the normal and the adventitious buds of trees. The 
latter he regards as new individuals of the same species as the 
tree from which they spring, or as apogamic embryos, while the 
former are simply organs for prolonging the life of the indi- 
vidual. It is quite common for the first leaves of a woody plant 
to differ in form or structure from the later leaves. Examples 
NO. 1562, VOL. 60] 
are given in Lucalyptus globulus, the walnut, the horse-chestnut, 
and the hornbeam. In all these cases the first leaves from 
adventitious buds resemble, not those from normal buds, but the 
first leaves of the young plant. 
A SECOND edition of Dr. M. M. Richter’s tables of carbon 
compounds is in course of publication by the firm of Leopold 
Voss, Hamburg and Leipzig (London: Williams and Norgate), 
under the revised title of ‘* Lexikon der Kohlenstoff-Verbin- 
dungen.’’ How tremendous has been the advance in the know- 
ledge of carbon compounds since the original work appeared 
may be judged by the fact that the total number of compounds. 
registered in the new edition is 67,000, as compared with 
16,000 known in 1883. The work will be an index to Beil- 
stein’s handbook of organic chemistry, for all the compounds— 
about 57,000—contained in Beilstein are dealt with. Papers 
published up to the end of last year have been used in the 
preparation of the volume, and it is intended to publish annual 
supplements in order to keep the work up to date. The 
“* Lexikon” will be completed in about thirty-five parts, twelve 
of which have been issued. 
Messrs. WHITTAKER AND Co. have published a second 
edition, thoroughly revised, of ‘‘ An Introductory Course of 
Practical Magnetism and Electricity’ by Mr. J. Reginald 
Ashworth. The book contains an admirable course of ex- 
perimental work suitable for students in ‘‘ Schools of Science” 
and other institutions where physics is taught by laboratory 
practice. A number of new illustrations have been added to 
assist students to understand descriptions of experiments. 
CALENDARS, for the session 1899-1900, have reached us from 
the Merchant Venturers’ Technical College, Bristol, and the 
Birkbeck Institution, London, in each of which all necessary 
information is to be found as to the various activities in con- 
nection with the two institutions. We notice that at the 
Merchant Venturers’ College certain extensions and improve- 
ments have recently taken place ; ¢.g. a new optical laboratory 
has been opened in connection with the Department of Applied 
Physics and Electrical Engineering, the amount of space avail- 
able for the dynamo and testing-room has been doubled, and a 
battery, &c., have been added to the equipment. In addition to 
these, other changes have either taken place or are in progress. 
Two articles of scientific interest are to be found in the 
current issue of the Mzmanztarian—one, by Mr. E. W. 
Brabrook, entitled ‘‘ Anthropology, 1863-1899”; the other, 
by Dr. D. Somerville, on ‘‘The Rise of Bacteriology.” Each 
gives in brief outline some idea as to what has been accom- 
plished in the two branches of science. A reproduction of a 
striking photograph of Mr, Brabrook forms a frontispiece to the 
number, 
WE are asked to say that the lectures to young people, referred 
to in the last issue of NATURE, p. 538, are to be delivered by 
Mr. Cecil Carus-Wilson during the months of October and 
November, and not as was stated. 
THE additions to the Zoological Society’s Gardens during the 
past week include five Barbary Turtle Doves (Zzrtur rzsorius) 
from Africa, presented by Mrs. J. A. Moore; one Ruffed 
Lemur (Levzwx~ varius) from Madagascar, two Westermann’s 
Eclectus (Zclectus westermannz) from Moluccas, a Two-spotted 
Paradoxure (Paradoxurus binotata) from West Africa, a Rufous 
Tinamon (Rhynchotus rufescens) from Brazil, a Grey Ichneumon 
(Herpestes gréseus) from India, four Blanding’s Terrapins (Zyzys 
blanding?) from North America, deposited; a Black-necked 
Swan (Cygnus négrécollis) from Antarctic America, a Hoopce 
(Upupa epops), two Sandpipers (Zrzngo¢des hypoleucus), 
European, two Lanceolated Jays (Garru/us lanceolatus) from 
the Himalayas, purchased. 
