February 27, 1919] 



NATURE 



'v '■■■ 



■ '■•'• '. .'•!'. •'•VV' ' •'- :: 



y^-'i 



■ 



^ 



■*£»->.. 



un&nMnen4 



in endorsing our claim that the Coolidge 

 Tube provides them with an instrument of 

 precision far in advance of any previously 

 produced. 



This is what they say : — 



" TIil- Coolidge Tube possesses, among other advantages over 



ordinal \ X-Ray Tubes, the quality of extreme adaptability." 

 "It can be used continuously over long periods without risk of 



damage to the tube, with currents of any strength likely to be 



required for examinations." 

 " Fen single-flash exposures it constitutes the ideal tube." 

 "You cm sel the Coolidge Tube to do a certain thing in a 



certain lime and you can rely on it doing the same thing each 



time." 



TAe 



X-Ray Tllbe 



CooIidL— Tubes aie avai.'ablc for imirediate d'l.vry from Stocks in London. They 

 Smhe, •'.'. the princi.al dealers in X-ray apparatus. 



The British Thomson-Houston Co., Ltd., 



(Owners of the Britisli Patents) 

 Mazda House, 77, Upper Thames Street, London, E.C. 4. 





• : 



m 





H 



m 



