Two Cambosco Instruments 



32-254 TRANSPIRATION App. 

 Detmer P. 214. 



Garreau's 



To determine the amount of transpiration 

 from the upper and lower sides of a leaf at 

 the same time. Complete, . . . $4.50 



32-256 TRANSPIRATION CHAMBER, 

 Detmer, P. 219. 



To show that the amount of transpiration 

 depends upon the degree of moisture in the 

 air and that a rising temperature accelerates 

 32-254 transpiration. The m/e of transpiration in ^^3; 32.256 



air and in 7noist is easily determined. Without burner or thermometer, $5.00. 



SEE Botanical Catalog, 91, P. 49, for complete information. 



CAMBRIDGE BOTANICAL SUPPLY COMPANY 



WAVERLEY, MASS. 



Leading American Makers of Physiological Apparatus 

 Laboratory Equipment for all the Sciences 



Established 1884 Catalogue Free Mention Plant World 



LIGHT FILTERS 



We are able to supply a series of glass screens which absorb or transmit various 

 parts of the spectrum and are useful for experimental work in growth, photo- 

 tropism, and photosynthesis. These glass screens were developed by Dr. D. T. 

 MacDougal, and are now available in bell-jars 36 x 36 cm. in size, with perforated 

 top, or in plates 16.5 cm. square. 



Red Plates. A good monochrome transmitting to .610 u $1.50 each 



Blue Plates. Transmitting wave lengths less than .510 u $1.50 each 



Orange Plates. High transmission in red and green to .530 u. 



Bridges the spectrum from red to blue $1.00 each 



Heat-Absorbing Plates. Absorb most of the infra-red and 97% 

 of the heat of a Nernst lamp. Give a pyrheUometer reading 

 about half that of good window glass. Transmit 65% of inci- 

 dent white light. In plates only $1.00 each 



Uviol Plates. Transparent to visible spectrum, transmitting 

 ultra-violet to .310 u. in sheets 6 mm. thick to .300 u. in 

 sheets 3 mm. thick. In plates only $1.00 each 



Terms for bell-jars furnished on request. Additional information 



cheerfully given 



THE PLANT WORLD TUCSON, ARIZONA 



