u 



SCIENCE.— AD VER TISEMENTS. 



SCIENTISTS needing temporary or perma^ 

 nent assistance of accurate stenographer, able 

 to edit manuscripts, etc., should address 

 EXPERIENCE, Care of " Science," 



66 Fifth Avenue, New York. 



ricQill University, Hontreal 



CHAIR OF 

 ELECTRICAL ENQINEERINQ 



The Board of Goveruors is prepared to re- 

 ceive applications for the W. C. McDonald Chair 

 of Electrical Engineering. Salary, not less than 

 $2,000, per annum. Applications, accompanied 

 by any testimonials which candidates may de- 

 sise to submit, should reach the undersigned on 

 or before 20th June next. 



W. Vaughan, 

 Secretary, McGill University, Montreal. 



ricQill University, Hontreal 



CHAIR OF PHYSICS 



The Board of Governors is prepared to receive ap- 

 plications for one of the W. C. McDonald Chairs of 

 Physics, vacant by the recent appointment of Prof. 

 Callendar, M.A., F.E.S., to the Quain Chair of Phys- 

 ics in University College, London. Salary, §2,500 

 per annum. Applications, accompanied hy any testi- 

 monials -which candidates may desire to submit, 

 should reach the undersigned on or before the 20th 

 June next. ^ Vaughan, 



Secretary, McGill University, Montreal. 



SIXTH EDITION. 



THE 



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