clxxvi NATURE [DECEMBER 25, 1913 
eitz  |J. H. STEWARD’S 
. BAROGRAPHS 
NEW AND Giving a continuous record of atmospheric 
IMPROVED pressure. 
MICROSCOPES | [= 
SUITABLE FOR 
EVERY 
REQUIREMENT 
(from class work 
to the highest 
grade research) 
in a variety of models, 
possessing many advan- 
tages over the older = 
type, and embodying 
several important fea- | THE EDUCATIONAL BAROGRAPH, with $3 15 0 
tures not to be found ink and charts for one year ie 
in any others. Size 12 x 64 x 64 inches. f* 
OTHER BAROGRAPHS in VARIOUS PATTERNS 
Illustrated from £4 4 O to £12 12 O 
Descriptive 
Sectional 
Catalogues J. H. STEWARD, Ltd., 
on request. 
Opticians & Scientific Instrument Makers to the British & Foreign Govls., 
18 BLOOMSBURY SQUARE, W.C. | 406 & 457 STRAND, LONDON. 
(A few doors from the British Museum.) ESTABLISHED 1852. 
WATSON’S NEW APPARATUS 
British made at Barnet, Herts. 
Illustrated Catalogue, Part Il, Post Free. 
Guaranteed for 5 Years. 
A Metallurgical List has just been issued, and includes 3 NEW MICROSCOPES, ’ 
THE “VULCAN” MICROSCOPE. For examination of metals in course of manufacture. The vertical illuminator and illuminant are 
integral parts ot the Microscope. lhe lamp is a q volt metal filament, and current obtained from a small battery. 
THE “WINDER” MICROSCOPE, Designed for examination of metals under strain when being tested. Molecular changes can be ub-erv d 
visually, photographically. or by projection. Is fitted with the new Condenser Vertical Illuminator. 
NEW “ MICROMETER” MICROSCOPE. For exact measurements of screws, &c. Reads by verniers and by a micrometer. Absolutely 
reliable and free from backlash usually associated with these instruments. 
NEW CONDENSER VERTICAL ILLUMINATOR. Consists of a tube containing a series of condensing lenses and a small electric — 
lamp. ‘Iwo iris diaphragms are fitted, and the instrument gives a total freedom from glare. { 
OTHER NEW APPARATUS :—RADIAL SWING-OUT FITTINGS FOR UNDERSTAGE AND SUBSTAGE CONDENSERS. 
THREE JAW OBJECTIVE CHANGER, obviates use of revolving nosepiece. DUPLEX EYEPIECE, for demonstr-tion purposes. _ 
LABORATORY ELECTRIC LAMP. REFLECTOR POLARISER, designed by Mr. F. J. CuEsHixe, B.A. DIFFRACTION 
MICROMETER EYEPIECE, designed by Mr. J. W. Gordon. 
Fullest details and prices of the above will be found in the NEW METALLURGICAL CATALOGUE and the 
SUPPLEMENTARY MICROSCOPE LIST. Gratis on request. 
W. WATSON & SONS, Ltd. (**9337"**), 313 High Holborn, London, W.C. 
Optical Works—HIGH BARNET, HERTS. 2 EASY ROW, BIRMINGHAM. 
{16 FORREST ROAD, EDINBURGH. Depots {212 NOTRE DAME STREET WEST, MONTREAL. 
Branches | 1g4 GREAT PORTLAND STREET, LONDON, W. 78 SWANSTON’ STREET, MELBOURNE, AUSTRALIA. 
NEW SPENCER ROTARY MICROTOME. == 
No. 820. £20: 12: 0 
A Rotary Microtome which will cut accurate sections 
of a definite thickness, each section having the same 
thickness as its neighbour. 
IT IS ACCURATE, CONVENIENT, AND RELIABLE. 
PRICE LIST ON APPLICATION. 
SOLE AGENTS for Great Britain and Ireland (except London)— 
STANDLEY BELCHER & MASON, Ltd., Church St, BIRMINGHAM. 
Printed by Richarp CLay & Sons, Limirep, at Brunswick Street, Stamford Street, S.E., and published by MacmiLLan AND Co., LimiTEp, at’ 
St. Martin's Street, London, W.C., and THe Macmitian Co., 66 Fifth Avenue, New York.—Tuurspay, December 25, 1913. 
