SCIENCE 



New Series. 

 Vol. IX. No. 21S. 



Friday, March 3, 1S99. 



Single Copies, 15 cts. 

 Annual Subscription, $5.00. 



FOSSILS. 



Static Machines X=Ray Apparatus 



for all purposes. send for bulletin No. 24. and Supplies 



SWEET & LEWIS CO., 9 Bromfield St., Boston. Mass. 



The attention of Teachers of Geology and Physiography is 

 called to our systematic collections of Fossils ; $20.00 and 



upwards. We also make up Special Collections to illustrate the different text-books. 



Our new circular on American Palaeozoic Coeals, Bbachiopod and Trilobite 



Models, will be mailed on request. 



WARD'S NATURAL SCIENCE ESTABLISHMENT, ROCHESTER, N. Y. 



MINIATURE IITCAITDESCENT LAMPS. 

 MINIATURE LAMP RECEPTACLES. 

 ) X-RAT TUBES AND APPARATUS. 

 FLUOROSCOPES ^— . 



Catalogu.es on Application. 



Edison Decorative and Miniatnre Lamp Department, 



(General. Electric Company,) 



HARRISON, N. J. 



Projection Apparatus 



^9»mmm^»9wm-»mm9-^»»^»^9-i 



"For lecture purposes (and also as a source of light for Scientific Projection) the ' Ideal ' 

 Lantern Style B, is to be recommended very highly. It is constructed along approved lines 

 in every respect and is probably the most compact apparatus on the market that makes use of an 

 Arc Lamp. The Thompson 90° Arc Lamp is generally acknowledged as far more eSicient 

 than other types, producing greatly iacreased illumination for given consumption of energy." — 

 Biddle's Bulletin, January, 1899. 



JAMES G. BIDDLE, 



909 Drexel Building, Philadelphia. 



Write for Pamphlet 250 



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