OcToBER 9, 1913] 
: MINERALOGY—CRYSTALLOGRAPHY— 
PETROGRAPHY—GEOLOGY. 
Ask for our new 
GENERAL CATALOGUE XVIII. 
(2nd Edition) 
for the use of Middle and High Schools and Universities. 
Part I, 260 pages, 110 Illustrations. 
This catalogue has been prepared with the view of making an exhaustive 
compilation of all educational appliances for the teaching 
of Mineralogy and Geology from a scientific as well as from 
a practical point of view. All the subjects are treated typically, and 
instructive specimens have been selected with the greatest care. A close 
examination of the catalogue will show, that owing to its careful compo- 
sition it gives the opportunity of procuring the most complete outfit for the 
various schools for instruction in and the study of the subjects named, 
Catalogue No. 18, Part I, will be sent free on application. 
Part II will appear within the course of the year. 
(Collections and single specimens of Minerals and Fossils, 
Meteorites bought and exchanged.) 
Dr. F. KRANTZ, 
RHENISH MINERAL OFFICE, BONN-ON-RHINE, GERMANY, 
Established 1833. Established 1833. 
ROCK SECTIONS FOR THE MICROSCOPE 
New List of over 600 well cut Rock and Mineral 
Sections now ready, post free from 
JAMES R. GREGORY & CO., 
Mineralogists, Gc., 
189 FULHAM ROAD, SOUTH KENSINGTON, S.W. 
Telephone: 2841 Western. 
Telegrams: ‘‘ Meteorites, London.” 
LIVING SPECIMENS FOR 
THE MICROSCOPE. 
Volvox, Spirogyra, Desmids, Diatoms, Amceba, Arcella, Actinospherium, 
Vorticella, Stentor, Hydra, Floscularia, Stephanoceros, Melicerta, and many 
other specimens of Pond Life. Price xs. per Tube, Post Free. Helix 
pomatia, Astacus, Amphioxus, Rana, Anodon, &c., for Dissection purposes. 
THOMAS BOLTON, 
25 BALSALL HEATH ROAD, BIRMINGHAM. 
MARINE BIOLOGICAL ASSOCIATION 
OF THE UNITED KINGDOM. 
THE LABORATORY, PLYMOUTH. 
The following animals can always be supplied, either living 
or preserved by the best methods :— 
Sycon; Clava, Obelia, Sertularia; Actinia, Tealia, Caryophyllia, Alcy- 
onium; Hormiphora (preserved); Leptoplana; Lineus, Amphiporus, 
Nereis, Aphrodite, Arenicola, Lanice, Terebella; Lepas, Balanus, 
Gammarus, Ligia Mysis, Nebalia, Carcinus; Patella, Buccinum, Eledone, 
Pectens Bugula, Crisia, Pedicellina, Holothuria, Asterias, Echinus, 
Salpa (preserved), Scyllium, Raia, &c., &c. 
For prices and more detailed lists apply to 
Biological Laboratory, Plymouth. 
THE DIRECTOR. 
munications to the Editor. 
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NATURE 
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Ixiii 
WATKINS & DONCASTER, 
Naturalists and Manufacturers of 
CABINETS AND APPARATUS 
FOR COLLECTORS OF INSECTS, BIRDS' EGGS AND SKINS 
MINERALS, PLANTS, &c. 
N.B.—For Excellence and Superiority of Cabinets and Apparatus, 
references are permitted to distinguished patrons, Museums, Colleges, &c. 
A LARGE STOCK OF INSECTS, BIRDS’ EGGS AND SKINS. 
SPECIALITY.—Objects for Nature Study, 
Drawing Classes, &c. 
Birds, Mammals, &e., Preserved and Mounted by First-class 
Workmen true to Nature. 
All Books and Publications (New and Second-hand) on Insects, 
Birds’ Eggs, &c., supplied. 
36 STRAND, LONDON, wW.C. 
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FOLL CATALOGUE POST FREE. 
Sales by #Huction. 
STEVENS’ AUCTION ROOMS. Estp. 1760. 
A Sale by Auction is held EVERY FRIDAY 
at 12.30, which affords first-class opportunities for the disposal or 
ea of SCIENTIFIC AND ELECTRICAL APPARATUS, 
icroscopes and Accessories, Surveying Instruments, Photographic 
Cameras and Lenses, Lathes and Tools, Cinematographs and Films, 
and Miscellaneous Property. “gt 
Catalogues and terms for selling will be forwarded on application to 
Mer. J. Cc. STEVENS, 
38 KING STREET, COVENT GARDEN, LONDON, W.C. 
THE x-RAY TUBE, 
Price 15/- 
Sole Maker, 
H. HELM, 
66 Hatton Carden, 
London. 
ACTUAL MAKER 
of all kinds of 
X-Ray and Vacuum 
Tubes, &c. 
LIST FREE. 
*SiRiVUs” 
Collections of British and Foreign 
MINERALS, ROCKS, FOSSILS. 
25 Specimens, 5/6; 50 do., 10/6; 100 do., 21/-; 200 do., 4.2/-. 
20 Coal Measure Rocks and Fossils, 12/6; do., larger, 15/-. 
In Polished Deal Boxes. 
Inspection invited of a large stock of Minerals, Rocks, Fossils, and 
Microscopic Objects. Specimens sent on approval, 
Prospectors’ Sets, Blowpipe Cases, Cabinets, Geologists’ 
Hammers, Card Trays, Glass-Capped Boxes, Models of Crystals, 
and all Apparatus for Mineralogists and Geologists. 
NEW CATALOGUES POST FREE. 
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