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NEw SERIEs, y SINGLE COPIES, 15 CTS. 
VoL. X. No, 240. FRIDAY, AuGUST 4, 1899. P ANNUAL SUBSCRIPTION, $5.00 
4 WM. GAERTNER & CO. 
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 
34-inch Telescope SPECTROSCOPES DIVIDING ENGINES, COMPARATORS 
on Universal Mounting MICHELSON INTERFEROMETERS GENERAL LABORATORY APPARATUS 
Price, $150.00 BOLOMETERS UNIVERSAL LABORATORY SUPPORTS 
MINIATURE INCANDESCENT LAMPS. 
MINIATURE LAMP RECEPTACLES. 
X-RAY TUBES AND APPARATUS. 
FLUOROSCOPES. 
Catalogues on Application. 
Hdison Decorative and Miniature Lamp Department, 
(GENERAL ELECTRIC CompPany,) 
HARRISON, WN. J. 
= We have many meteorites for sale, among which are two 
Meteorites. recently discovered ones: the aerolite Ness County recently 
described; and the siderite Murphy to be described in September issue American Journal of 
Science. Circulars on application. We also desire to purchase meteorites. 
WARD’S NATURAL SCIENCE ESTABLISHMENT, 28 to 40 College Ave., Rochester, N. Y. 
poo o FFF F F828 FF BSS SIS 3 DSSS DS IIBOIFIIIOD 3DSDIIIIIIISIIIIII229, 
v 
; Apparatus for Wireless Telegraphy % 
N Ww 
a An inexpensive but reliable outfit ; for colleges and schools as well as general experimenters. 7 
a Comprising Special Induction Coil, Oscillators, Morse Key, Receiver with adjustable Co- 4 
Zz herer, four-inch vibrating bell, specially wound high relay and necessary battery. ¥ 
: Net Price for Complete Outfit (for distances up to 200 feet) $40 00. 4 
® 
The subject of wireless telegraphy Y 
Ps is exciting such great interest JAM ES G. BIDDLE W 
that every laboratory should be on =i9 : : W 
4 Eq uipDEdonienmentments 1034 Drexel Building, Philadelphia, Pa. ¥ 
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