SCIENCE-ADVERTISEMENTS 



VAN SLYKE APPARATUS 



For the determi- 

 nation of dioxide 

 and carbonates in 

 blood plasma. 



FREDERICIA APPARATUS 



^' For the determi- 



nation of CO„ in 

 Alveolar Air. 



153 East 84th Street 



E, MACHLETT & SON 



New York City 



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 w^ith: 



T. W. THOMAS 

 Spear Laboratory, Oberlln, Ohio 



MUSHROOM BOOK 



and large colored chart 

 postpaid for $2.00 



Specially prepared for beginners who wish to 

 learn the edible and poisonous kinds. 

 Dr. W. A. Murrill, N. Y. Botanical Garden, 

 NEW YORK CITY 



SCISSORS, FORCEPS, KNIFE, NEEDLE- 

 HOLDER, CLAMP, DRESSING SHEARS 



Refer to 5921. 



THELCO CONSTANT TEMPERATURE 

 DRYING OVENS 



Medal of Merit, Franklin Institute 



Send for data on latest things. 



DR. H. E. WETHERILL'S SPECIALTIES 



R. D. 1, PHOENIXVILLE, PA., U. S. A. 



LARGE DOUBLE WALL THELCO OVEN 



In the laboratory as 

 stantly apply economics, 

 expensive article will do 

 products you will find : 



less 



fell as in the mill we 



If for the work in 1 



ise it by all means. Among ou 



wide variety suitable for th 



different conditions at hand. 



Manufactured by 

 The Thermo Electric Instrument Co. 



8 Johnson St. 



New.\rk, N. J. 



