470 
BOOKS RECEIVED. 
Eloges Academiques et Discours. By G. Darboux. 
Pp. ili+525. (Paris: A. Hermann et Fils.) 5 francs. 
The Inter-relationships of the Bryophyta. By Dr. 
f. Cavers. (‘New Phytologist’ Reprint, No. 4.) Pp. 
vilit203. (Cambridge: Botany School.) 4s. 
Pygmies and Papuans: the Stone Age To-day in 
Dutch New Guinea. By A. F. R. Wollaston, with 
Appendices by W. R. Ogilvie-Grant, A. C. Haddon, 
and S. H. Ray. Pp. xxiv+352+plates+maps. 
(London: Smith, Elder and Co.) 15s. net. 
The Composition of Matter and the Evolution of 
Mind. By D. Taylor. Pp. 176. (London and Fell- 
ing-on-Tyne: Walter Scott Publishing Co., Ltd.) 
3s. 6d. 
Notes sur la Physique et la Thermodynamique. 
E. H. Amagat. Pp. v+146. 
et Fils.) 6 francs. 
Non-Euclidean Geometry. By Prof. R. Bonola. 
Translated by Prof. H. S. Carslaw. With an Intro- 
duction by Prof. E. Enriques. “Pp. xii+268. 
(Chicago: The Open Court Publishing Co.) 2 dollars 
net. 
The Teachers’ Book of Constructive Work for 
Elementary Schools. By E. J. S. Lay. Pp. xii+142. 
(London: Macmillan and Co., Ltd.) 3s. 6d. net. 
By 
(Paris: A. Hermann 
Treatise on Light. By Christiaan Huygens. Ren- 
dered into English by Silvanus P. Thompson. Pp. 
xii+128. (London: Macmillan and Co., Ltd.) tos. 
net. 
The Depths of the Ocean. By Sir John Murray 
and Dr. J. Hjort. With contributions from Prof. A. 
Appellof, Prof. H. H. Gran, and Dr. B. Helland- 
Hansen. Pp. xx+821. (London: Macmillan and 
Co., Ltd.) 28s. net. 
Sir Joseph Dalton Hooker, O.M., F.R.S., &c. An 
Oration by Prof. F. O. Bower. Pp. 36. (Glasgow: 
J. MacLehose and Sons.) 
South-Eastern Agricultural College, Wye. Report 
on Economic Mycology for 1911. By E. S. Salmon. 
Pp. 55. (London and Ashford : Headley Bros.) 1s. 6d. 
Lehrbuch der Zoologie. By Prof. R. Hertwig. 
Zehnte Auflage. Pp. xii+675. (Jena: G. Fischer.) 
11.50 marks. 
Elementary Quantitative Analysis. By Dr. W. Briggs. 
and H. W. Bausor. Pp. viii+122. (London: W. B. 
Clive.) 2s. 
University of Pennsylvania. The Museum. Pub- 
lications of the Babylonian Section. Vol. ii, No. 1: 
Business Documents of Murashu Sons of Nippur, 
dated in the Reign of Darius I]. By A. T. Clay. 
Pp 54+123 plates. Vol. ii., No. 2: Documents from 
the Temple Archives of Nippur, dated in the Reigns 
of Cassite Rulers. By A. T. Clay. Pp. 55-92+plates 
1-72. (Philadelphia : The University Museum.) 
Studies in Radio-activity. By Prof. W. H. Bragg. 
Pp. x+196. (London: Macmillan and Co., Ltd.) ss. 
net. 
The Local Incidence of Cancer. By C. E. Green. 
Pp. 36. (Edinburgh and London: W. Green and 
Sons.) 1s. net. 
A Guide to the Dissection of the Dog. 
By Dr. 
O. C. Bradley. Pp. viiit+24r. 
(London: Longmans 
and Co.) tos. 6d. net. 
An Introduction to the Theory of Statistics. By 
G. U. Yule. Second edition. Pp. xv+381. (London: 
C. Griffin and Co., Ltd.) 10s. 6d. net. 
Modern Copper Smelting. By D. M. Levy. Pp. 
NO. 2227, VOL. 89] 
NATURE 
| Pp. ix+313. 
* International Commission on Mathematical Teaching. 
[quay 4, 19Le2 
xi+259. (London: C. Griffin and Co., Ltd.) tos. 6d. 
“net. 
The Main Drainage of Towns. By F. N. Taylor. 
(London C. Griffin and Co., ‘Ltd.) 
12s. 6d. net. 
FORTHCOMING CONGRESSES. 
Juty 8-12.—Museums Association. Dublin. President : Count G. N- 
Plunkett. Secretary: E. E. Lowe, The Museum, Leicester. 
Jury 15-19.—Celebration of the 250th anniversary of the Royal Society. 
London. 
JULY 24-30.—First International Eugenics Congress. London. Presi- 
dent: Major Leonard Darwin. Secretary: Eugenics Education Society, 
6 York Buildings, Adelphi. 
JuLy 25-28.—Congress of the Royal Institute of Public Health. 
Address: Russell Square, W.C. 
Juty 29-AuGcusr 3.—Royal Sanitary Institute. 
Buckingham Palace Road, S.W. 
Berlin. 
York. Address : go 
AuGustT 5-10.—International Congress of Entomology. Oxford. Presi- 
dent: Prof. E. B. Poulton. General Secretary: Dr. Malcolm Burr, c/o The 
Entomological Society of London, r1 Chandos Street, W. 
AuGustT 22-28.—(i) International Congress of Mathematicians, and «(ii) 
President : Prof. 
Treasurer : Sir J. Larmor, F.R.S., St. John’s College, Cambridge. 
SEPTEMBER (first week) —International Congress of Anthropology and 
Prehistoric Archeology. Geneva. 
Klein. 
SEPTEMBER 4-11.—British Association. Dundee. President : Prof. E. A. 
Schafer, F.R.S. Assistant Secretary : O. J. R. Howarth, Burlington House, 
London, W. 
SEPTEMBER 4-13.—International Congress of Applied Chemistry. Wash- 
ington, D.C. President: Dr. W. H. Nichols. Secretary : Dr. B. G. Hesse, 
25 Broad Street, New York City, U.S.A. 
SEPTEMBER 8-r1.—Société Helvétique des Sciences Naturelles. Altdorf. 
President: Dr. P. B. Huber. Secretaries: Prof. J. Briilisauer (German) 
and M. P. Morand Meyer (French), Altdorf. 
SEPTEMBER 23-28.—International Congress on Hygiene and Demography. 
Washington. President: Dr. H. P. Walcott. Secretary-General: Dr. J. 5. 
Fulton, Army Medical Museum, Washington, D.C. 
CONTENTS. PAGE 
Statistics of Magnetic Change, By W. W. B. 445 
Introduction to the Study of Heredity . 445 
Mineral Localities Be fd One ae 446 
Microscopic Anatomy. By G.E.S. . 447 
Mechanics and Theoretical Physics 447 
Our Bookshelf 449 
Letters to the Editor :— 
Hybrid Sea-urchins.—Prof. E. W. MacBride, 
F.R.S. PESO oe fol at 45° 
July Meteor-showers.—John R. Henry. ..... 450 
Prof, Garstang’s Excavations in Northern Syria 
andinthe Sudan. (J//ustvafed.) . 451 
‘Committee on Sight Tests for Seamen 453 
Mr, Balfour on Francis Bacon. 5 cones 454 
Floris Osmond, By Dr. Walter Rosenhain 454 
Notes Mee MES ym, 6 455, 
Our Astronomical Column :— 
Astronomical Occurrences for July 459 
The Nova or Variable 87, 1911, Persei 459 
Perseids in August, 1911 . 459 
Observers’ Handbook . : 459 
Variable Stars of Special Interest . 459 
Search-ephemerides for Comets . Sopp co Ge 
The National Museum of Wales. (/Mustrated.). . 460 
Reports of Meteorological Observations _.. . . 461 
The Optical Properties of Muscle. (lth Diagram.) 
By Dr. T. Wingate Todd Syste ies “Reese 
The Manufacture of Nitrates from the Atmo- 
sphere. (///ustvated.) By Ernest Kilburn Scott. 463 
University and Educational Intelligence 465 
| Societies and Academies 466 
Books Received ’ : 470 
Forthcoming Congresses . 47° 
