June 8, 1905] 



NA TURE 



Iv 



HEELE'S 



FAMOUS 



SPECTROMETER 



The axis, carrying the divided circle 

 and observing-telescope, is carefully 

 ground into the exceedingly durable 

 cast-iron stand ; the collimator is firmly 

 connected with the stand, while the 

 divided circle and observing-telescope 

 can be turned about their axes 

 independently as well as together ; 



No. 6j. 



both have clamps and micrometer motion ; goniometrical determinations may also be done after WoUaston's method, and, 

 when a Gauss's eye-piece i-i used, according to GaUfS's method. . These spectrometers are especially for universal use, as 

 there is plenty of space between the telescopes, and supplied with circle divided into J°, reading to i minute by means of 

 verniers; collitiator and observing telescope have a diameter of J in. and a focal length of 7 in. ; with one eye-piece, 

 magnifying four times ; adjustable slit with micrometer-screw and comparison-prism. 



net. 



PETER KIEELE, 115 HIGH HOLBORN, LONDON, W.C. 



Maker of Physical, Chemical and other Instruments, and every kind of Spectroscope 



and Polarimeter. 



U,i,„,\ l-ri.r. r<l,is. lUOO: St. L„„is. l'.>04: anil <,tl,,r li h,h ,i irii ril.-.. Tih-tj ril nis : Arrtit ii:h-. I.i,,i,l<ii,. 



WHEATSTONE ELECTRIC LIGHT REFLECTING STEREOSCOPE 



ILLUSTRATED CATALOGUE 



VIEWING NEGATIVE PLATES. 



Made to take any size Plate. 

 Price comi'leti!, J36 lOs. 



ELECTRIC LIGHT BATHS O-f all 

 kinds. 



Special Illustrated List Post Free. 



MABtR^v mr. cox, x..tci., 



ACTUAL MAKERS of X Ray, Ac , Apparatus to the Admiralty. 

 War Office, Colooial Offi:e. Indian Government, 4c , 



la ROSEBERY AVENUE, k 15-21 LAYSTALL ST., 



LONDON, E.C. 

 tions to Beginners) Post Free. 



(BY .APPOINTMENT TO THE ROYAL INSTITUTION 

 OF GREAT BRITAIN.) 



WAVE MOTION. 



Makers of the new Apparatus illustrating Wave Motion, 

 designed and used by Dr. J. A. FLEMING in the 

 Christmas Lectures at the Royal Institution. 



CHARING 



%jm~ SPECIAL TERMS TO COLLEGES 



READING MICROSCOPES, RESISTANCE COILS, &c. 



CROSS ROAD, LOMDOI^, IflT.C. 



SCHOOLS, INSTITUTES, &c. 



