POROUS PORCELAIN CONES 



For Auto-Irrigation of Potted Plants 



The Porous Porcelain Cone may be in- 

 stalled and used for the auto-irrigation of 

 plants in pots, greenhouse benches or outdoor 

 beds in the same manner as the other forms of 

 auto-irrigation cups that have long been in use. 



The dimensions of the Cone are, conical 



- portion: 7.5 cm. to 2.2 cm. in diameter, 6.1 

 L-, cm. high; cylindrical neck: 2.2 cm. in diameter, 



— 3.7 cm. high. 



Further particulars regarding the Porous 

 Porcelain Cone and its use will be given on re- 

 quest, or may be found in The Plant World, 

 Vol. 21, pp. 202-208, Aug. 1918. 



Porous Porcelain Cones, $0.75 each, $7.00 per ten 



Special Cones, with a part of the surface waterproofed as 

 desired, will be furnished at an extra cost of 25 cents each. 



THE PLANT WORLD 



TUCSON, ARIZONA 



BLACK SPHERICAL 



ATMOMETER CUPS 



This is a porous porcelain sphere with matt black surface. The 

 dimensions and other specifications correspond to those of the white 

 spherical cup. The black spheres are sold only in the standardized 

 condition, being calibrated in terms of the spherical standard. They 

 may be operated with standardized white spheres for the measure- 

 ment of solar radiation, or may be used alone for the measurement 

 of evaporation in any work involving the rates from dark surfaces. 



For literature on the use of the Black Spherical Atmometer Cup 

 see The Plant World, Vol. 18, pp. 21, 51, 95, 143, or the pamphlet 

 "Atmometry and the Porous Cup Atmometer." 



Standardized Black Spheres, $3.80 each, $36.00 per ten 



THE PLANT WORLD 



TUCSON, ARIZONA 



