CCXXXViI NATURE [FEBRUARY 5, I914 
eitz | ANEROID BAROMETERS 
FOR MEASURING THE ALTITUDE 
NEW OF MOUNTAINS OR BALLOONS. 
HIGH POWER mentscompensaed fr 
BINOCULAR 
MIGROSCOPE 
suitable for  ordi- 
With Altitude Scale 
reading up to 10,000 
feet and divided to 
every 50 feet. 
£35 10 O . 
With Altitude Scale 
to 15,000 feet and 
divided to 100 feet. 
£4 4 0 
With Altitude Scale 
to 20,000 feet and 
divided to 100 feet. 
£5 5 0 | 
IMustrated Catalogue, Part II, Post Free. 
Bey ae Mie on application J. H. STEWARD, Ltd. 
{ 
nary eyepieces and 
objectives, from 
the lowest to 
the HIGHEST 
POWERS, | in- 
cluding oil 
immersion 
objectives. 
partite stihl aE it 
Particulars 
Jor Leaftet No. 20, post free. Opticians & Scientific Instrument Makers to the British & Fo eign Govls. 
18 BLOOMSBURY SQUARE, W.C. 406 & 457 STRAND, LONDON. 
(A few doors from the British Museum. ) ESTABLISHED 1852. 
Guaranteed 
ayienin To) Awe 
& COPES. 
Will lasta 
lifetime. Mi CRO NS) 
British Made at Barnet, Herts. Constructed on Scientific Principles for Scientific Work 
This instrument is to be found in all Laboratories where precise work is a sine gud mon. It embodies every con- 
venience for comfort, accurate and rapid work. Each working part is slotted and sprung so that wear cantbe 
instantly compensated for. Compound substage provided with rackwork focussing and screw centering movements ~ 
The experience of vears proves that Watson’s Lever Fine Adjustment is unexcelled. 
PRICE—“‘H”’ Edinburgh Students’ Microscope, Stand only = Aas ats . £10 26 
“HH” Edinburgh Students’ Microscope, with Obiectives 2/3” and 1/6” N.A. 
0°74 with one millimetre of working distance, Eyepieces Nos. 2 and 4, Double Nose- 
piece, Aplanatised Abbe Illuminator with Iris Diaphragm. Complete in Mahogany Case 4316 8 8 
1/12” Oil Immersion Objective N.A. 1°30, new computation, giving a very flatfield £5 
WATSON’S MICROSCOPE CATALOGUE No. 2 gives full particulars of over 27 different Models and every k 
of 
Accessory, 
Microscopes and Apparatus oe Histology, Botany, Biology, Bacteriology, Petrology, Metallurgy, &c., &c. 
rojection and Photo-micrographic Outhts. 
W. WATSON & SONS, Ltd., Optical Works—HICH BARNET, HERTS. 
Established 1837. 313 High Holborn, LONDON, W.C. 
Branches—184 Great Portland Street London, W.C. 16 Forrest Road, Edinburgh. 
Depots—2 Easy Row, Birmingham; 212 Notre Dame Street West, Montreal, Canada; 
'78, Swanston Street, Melbourne, Australia. 
SPENCER MICROSCOPES, 
MICROTOMES. &c. 
I9iI4 PRICE LIST feaby. 
Post free upon application to 
STANDLEY BELCHER & MASON, Ltd., 
se tdand (except Lenton), « GS Church St., Birmingham. 
Printed by Richarp Cray & Sons, Liwiren, at Brunswick Street, Stamford Street, S.E., and published by MACMILLAN anpD Co., LimiTED, at 
St. Martin's Street, London, W.C., and THe Macmitian Co., 66 Fifth Avenue, New York.—THurspay, February s, 1914. 
