SCIENCE 
N Ss. b SINGLE CoPiEs, 15 CTs. 
Vor Xx. No. 241. Fripay, Aucust 11, 1899. ANNUAL SUBSCRIPTION, $5.00 
(Queen 
4N-Inch Portable Induction 
Coil 
Outfit complete with QUEEN Self-Regulating Xz:Ray 
TUBE, FLUOROSCOPE, BATTERY, Ete. Price, $170 
This Coil, giving a very powerful discharge with heavy spark, is suitable for all classes of X-Ray 
work and at the same time for general laboratory work, setting up powerful oscillations 
when used for wireless telegraphy. 
Pamphlets on INDUCTION CoILs and on QUEEN SELF-REGULATING TUBE sent free on application. 
Queen & @Go., inc. 
J. G. GRAY, President 
Electrical and Scientific Instrument Works 
Bh Wear ironed 1010 Chestnut St., Philadelphia 
