SCIENCE 
NEW SERIES. 
SINGLE COPIES, 15 CTs. 
VoL. X. No. 249. FRIDAY, OcTOBER 6, 1899. ANNUAL SUBSCRIPTION, $5.00 
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 
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. 
Edison Decorative and Miniature Lamp Department, 
(GENERAL ELECTRIC ComPany,) 
HARRISON, WN. J. 
2 We make systematic collections of Minerals 
Se h feye) j C (@) | | e etl oO n Ss Rocks, Fossils, Vertebrate and Invertebrate 
————————————————————— | Animals) designed tomectithe wants|of instruc; 
tors in these various departments. We also have laboratory material for individual work along the same 
lines. Catalogues and circulars will be mailed to teachers upon application. 
WARD'S NATURAL SCIENCE ESTABLISHMENT, 28 to 40 College Ave., Rochester, N.Y. 
APPEL DIS IISE. SSS SS SS SSS SSS SS SS SS SS SS S559 SSS 2S3S52555 id dled eda) 
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» THE SOCIETE GENEVOISE : 
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i announce that JAMES G. BIDDLE, 1034 Drexel Bldg, Philadelphia, is sole selling agent in the Me 
his United States and Canada for all apparatus of their make, it being hoped that this concentration of x 
AN business into the hands of one representative will prove satisfactory to American clients. . 
a Orders and inquiries from the above territory should be addressed to Mr. Biddle, who will send post ~~ 
ay paid to any interested college professor a 176 p. illustrated catalogue (French, 1896 Edition) of “Soe. 4 
Lis Gen.” Physical Laboratory Apparatus, comprising—Dividing Engines, Standards of Length, Com- M4 
*& parators, Cathetometers, Micrometers, Spectrometers, Goniometers, Heliostats, Chronographs, Tele- wy 
as scopes, etc. : \ 
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ay Careful attention to “‘ Duty Free”’ importations for educational institutions. 
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