SCIENCE— ADVERTISEMENTS 



THELCO CONSTANT TEMPERATURE 

 DRYING OVENS 



LARGE DOUBLE WALL THELCO OVEN 



In the laboratory as well as in the mill we must con- 

 stantly apply economics. If for the work in hand a less 

 expensive article will do, use it by all means. Among our 

 products you will find a wide variety suitable for the 

 different conditions at hand. 



Manufactured by 

 The Thermo Oectric Instrument Co. 



8 Johnson St. Newark, N. J. 



By means of sliding-contacts the resistance value of 



Jagabi Rheostats 



can be varied from zero to full rating in exceedingly 

 small steps. 



They are eminently suited for, and are largely used 

 in Educational, Research and Industrial Laboratories. 



[f'rilc for lUustratcd Bulletin S g8o 



James G. BiDDLE, Philadelphia 

 :2iM3 arch street 



WANTED 



Formulae and Processes for Chemicals 

 used in the Pharmaceutical Trade. Ad- 

 dress: G, c|o Science, Garrison, N. Y. 



CHART MAKING 



University and college teachers desiring charts 

 made up to suit their own special needs, from 

 figures of their own choosing and arranging, in 

 black and white, or in colors, at relatively small 

 cost, are invited to correspond with: 



T. W. THOMAS 



Spear Laboratory, 



Oberlin, Ohio 



AdsCISflAllSSft 



Abbe Refractometer 



IMMEDIATE DEUVERY FROM 

 STOCK 



Abbe Refractometer $220.00 f.o.b.N.Y. 



Ordinary Thermometer_ 2.00 



$222.00 



Dipping Refractometer_$ I 52.00 



Auxiliary Prism 6.50 



Heating Trough A 16.50 



Certified Thermometer. 9.50 

 Stem Thermometer 1.50 



$186.00 



Harold M. Bennett 



U. S. AGENT 

 153 West 23rd St., New York City 



