SCIENCE 
NEW SERIES. 9 SINGLE CoPiE&s, 15 CTs. 
VoL. X. No. 253. Fripay, NOVEMBER Vv) 1899. ANNUAL SUBSCRIPTION, $5.00 
Astronomical and Physical Apparatus 
152-158 EAST 56TH ST., CHICAGO 
SPECIALTIES 
STANDARD APPARATUS OF NEW AND IMPROVED DESIGNS 
READING MICROSCOPES AND TELESCOPES 
ASTRONOMICAL TELESCOPES HELIOSTATS 
SPECTROSCOPES DIVIDING ENGINES, COMPARATORS 
MICHELSON INTERFEROMETERS GENERAL LABORATORY APPARATUS 
BOLOMETERS UNIVERSAL LABORATORY SUPPORTS 
MINIATURE INCANDESCENT LAMPS. 
MINIATURE LAMP RECEPTACLES. 
X-RAY TUBES AND APPARATUS. 
FLUOROSCOPES. 
Catalogues on Application. 
Kdison Decorative and Miniature Lamp Departunent, 
(GENERAL ELECTRIC ComPany,) 
HARRISON, WN. J. 
We have a large stock of ancient stone implements, carvings, 
Archaeology and Ethnology pipes, etc., from America, Europe and other parts of the 
es §8§69WOCL. Keyptian Mummies, Roman Lamps, Mound Builders 
and Aztec Pottery, casts of rare or unique objects, such as Cave Dwellers’ Carvings, inscriptions from Assyria, 
the Holy Land, etc., ete. Modern Weapons and objects of domestic use from Australia, New Guinea, Africa, the 
Western Indians, etc. No catalogue; selections from stock shown by photographs, Write for quotations. 
WARD'S NATURAL SCIENCE ESTABLISHMENT, 28 to 40 College Ave., Rochester, N.Y. 
Catalogue B 
describes a great variety of high-class Measuring Instruments, intended for Electrical 
Engineering and Physical laboratories. It was issued Noy., 1898, and distributed 
quite freely at that time, but doubtless many interested in the subject were not on our 
list. I want any one who desires a copy, to send me his name now and the catalogue 
will be mailed to him free. The regular charge is 10 cents. 
Special facilities for supplying 
Electrical Measuring In- JAMES G. BIDDLE 
strumeuts of all standard 
N types at makers’ prices, 1034 Drexel Building, ; Philadelphia 
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