NOTE. 



The Instruments and Apparatus mentioned in this work 

 are made by, or can be obtained from, NEWTON & CO., 

 3 FLEET STEEET, LONDON, B.C., Opticians, Scientific 

 and Electrical Instrument Makers by Appointment to His 

 Majesty the King, H.E.H. the Prince of Wales, H.M. the late 

 Queen, His late R.H. the Prince Consort, the Admiralty, 

 War Department, H.M. Training Ships, the Indian and 

 Foreign Governments, the Board of Education, South Ken- 

 sington, tfc., and by Special Appointment to the Royal Institu- 

 tion of Great Britain. 



