SCIENCE— ADVERTISEMENTS 



FREAS CONSTANT TEMPERATURE 

 LABORATORY APPARATUS 



Small Freas Sensitive Water Thermostat 



An asset to any laboratory, particularly where 

 physical-chemical experiments are being car- 

 ried out. 



For sale by all reliable dealers. 



Manufactured by 



The Thermo Electric Instrument Co. 



8 Johnson Street, Newark, N. J. 



40EPZ 



Polariscopes 



for the sugar industry, 

 chemical laboratories and 

 the physician. 



Refractometers 



for testing butter, margar- 

 ine and other oils ana fats. 



These are now being furnished through 

 us as the exclusive distributors of optical 

 and scientific instruments manufactured 

 by C P. Goerz of Berlin. 



We have new designs. All instruments 

 are of the highes precision. 



Correspondence is invited. 



C. p. Goerz American Optical Co. 



319 P East 34lh Street, New York City 



^ARLZEisr 



JENA 



TERRESTRIAL and ASTRONOMICAL 

 TELESCOPES 



With Apochromatic and Achromatic 

 Objectives 



Telescopes with 60 to 130 ™/n, aper. 



Altazimuth and Equatorial Mountings 



for immediate delivery. 



Larger sizes on special order. 



Catalogues supplied on request. 



HAROLD M. BENNETT 



U. S. Agent 



153 West 23rd St., New York City 



