A WEEKLY 
ILEUSHRATED:) JOURNAL OF. SCIENCE. 
“To the solid g 
O; Nature trusts the mind which builds for aye.’ 
ryvouna 
>_-WORDSWORTH. 
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bo 
43 PaviOllu: 60] 
ENOARNSIDAYY-, MAY 25; 
1899. [PRICE SIXPENCE. 
Rezistered asa SESS at the General Post Office.] [All Rights are Reserved 
NEWTON FC eee | 
THE NO..1 “ TS ean CAMERA. 
SCIENTIFIC INSTRUMENT | 
MAKERS 
TO HER MAJESTY THE 
QUEEN 
AND THE GOVERNMEN' 
PHILOSOPHICAL INSTRU- 
MENT MAKERS BY SPECIAL 
APPOINTMENT TO THE 
Royat INSTITUTION OF 
GrEaT BritTAIn. 
Makers of every descrip- 
tion of OPTICAL and 
PHYSICAL APPARA- 
TUS of the highest class, 
for Colleges, Institutions, 
&e. 
Catalogue ot 
OPTICAL LANTERNS, 
PROJECTION APPARA- 
TUS, and SLIDES, 6¢. 
WIMSHURST ELECTRICAL MACHINES. 
Best Quality, 12 in., 70s. ; ; 18 in., 4610s. Multiple-Plate 
Machines, £20 to £150. jade for the Science and Art Depart- 
ment, and the Universities of Oxford, Cambridge, London, Sydney, 
N.S.W., McGill, Montreal, &c 
3 FLEET STREET, TEMPLE BAR, LONDON, E.C. 
SHORT BEAM BALANCES. 
CHEAP, QUICK-ACTING, 
ACCURATE, 
KNIFE EDGES AND PLANES OF AGATE 
Compensating Stirrup 
Suspenders. 
To carry-200, 500 grammes. 
Price £7. £9 9s. 
ASSAY BALANCES. 
ALUMINIUM BEams. 
5 Grammes in each Pan. 
‘Indicate J; m.g. 
£10 10s. and £7. 
CHEMICAL BALANCE. 
ALuMINIUM BEam. 
New design Sliding Rider. 
Tocarry 100 250 grms. 
Indicates 5 “yo m. 
_ £8 15s. _ £10 one 
WRITE for BALANCE CATALOGUE 
JOHN J. GRIFFIN & SONS, E 
20-26 SARDINIA STREET, LONDON, W.C. 
This Caner 
carries twelve 
+) pillaiteismin 
sheaths, which 
are changed ac- 
curately by a 
simple lever 
movement, which 
automati- 
registers 
also 
cally 
the 
made. 
exposures 
The lens is an 
achromatic ot 
quality with 
Diaphragm. 
The shutter 
arranged for time 
instantane- 
best 
Iris 
and 
ous exposures, 
and can be regu- 
lated at varying 
speeds. 
JAMES WOOLLEY, SONS & CO., LTD., 
VICTORIA BRIDGE, MANCHESTER. 
Complete Catalogue on application. 
£1 15 0.5 
Price, covered in best quality Morocco 
IMPROVED 
SELF-RECORDING 
RAIN GAUGE. 
DESCRIPTIVE 
PRICE LIST 
POST FREE. 
INVENTED AND MADE ONLY BY 
NEGRETTI & ZAMBRA, 
Scientific Instrument Makers to Her Majesty the Queen, 
38 HOLBORN VIADUCT, E.C. 
Branches— 45 CORNHILI, E.C., and 122 REGENT STREET, W. 
