lb bVO 



SCIENCE 



New Series. 

 Vol. IX. No. 231. 



Friday, June 2, 1899. 



Single Copie-s, 15 cxs. 

 Annual Sdbscription, ifS.OO 



U/M nAFRTNPP £ Pfl Astronomical and Physical Apparatus 



If III. UnLllillLR CU UU., 152-158 East 56th St.. CHICAGO 



LABORATORY TELESCOPE. 20 mm 



SPECIALTIES 



Astronomical Telescopes 



Spectroscopes 



MiCHELsoN Interferometers 



Dividing Engines, Comparators 

 General Laboratory Apparatus 

 Universal Laboratory Supports 



MIlSriATXTRE INCAITDESCEITT LAMPS. 

 MINIATURE LAMP RECEPTACLES. 

 X-RAY TUBES AND APPARATUS. 

 FLUOROSCOPES — . 



Catalogues on AppUoation. 



Edison Decorative and Miniature Lamp Department, 



(General. Electric Conipahy.) 



HARRISON, N. J. 



f^ M f^ — .»» ^^^ have recently added to this department many beautiful 



%^XL b ^jr6 SSJLS* I'ut gems, ready for mounting. A few of the more noticeable 

 ones are Yellow Sapphire, 1 ', k, S8 : Golden Topaz, l}k, lj8 ; Smoky Topaz, 4|k, !58 ; Diop- 

 side, l^k, $10 ; White Beryl, IJk, S5 ; Tourmaline, green, Ik, §3 and $i ; Tourmaline, rose, 

 ■■Sa.oO; Chrysoberyl, 3k, SS; Chrysoberyl, j ,'jk, i?7 ; Zircon, :2k, §7 ; Peridot, IJk, $4; 

 Variscite, &Uc. ; Amethyst, 5()c. to si. 50 ; Sapphire, $7 to $15 ; Aquamarine, $12 to |20 ; 

 Opals, oOc. to 98; Cameo's, ?1 to S3. 50, etc., etc. 



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



Apparatus for Wireless Telegraphy 



An inexpensive but reliable oiittit ; for colleges and schools as -well as general experimenters. 

 Comprising Special Induction Coil, Oscillators, Morse Key, Receiver with adjustable Co- 

 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. 



The subject of wireless telegrai)hy 

 is exciting such great interest 

 that every laboratory should be 

 equipped for exj^crimcnts. 



JA/V\ES G. BIDDLE 



1034 Drexel Building, Philadelphia, Pa. 



