BOTANICAL BOOKS 



AND SEPARATES OF JOURNAL ARTICLES 



Rocky Mountain Flowers, by F. E. and E. S. Clements. Cloth, 400 pp., 



profusely illustrated in color - - - - - - - --$3.00 



Living Plants and their Properties, by J. C. Arthur and D. T. MacDougal. 



Cloth, 234 pp., illustrated - - - - - - - - - 1 . 25 



Bibliography of Evaporation, by Grace J.Livingston. Paper, 121pp. - 1.25 



Atmometry and the Porous Cup Atmometer, by B. E Livingston. Paper, 



64 pp., illustrated - - - - - - - - - -.75 



Studies in Soil Physics, by E. E. Free. Paper, 42 pp. - - - - . 75 



The Deserts of Egypt, by D. T. MacDougal. Paper, 27 pp., illustrated - .40 



The Desert Basins of the Colorado River, by D. T. MacDougal. Paper 25 



pp., illustrated, map - - -.- - - - - - -.30 



An Improved Non-Absorbing Porous Cup Atmometer, by J. W. Shive. Paper, 



4 pp. ----------- - - .20 



Hybridization of Wild Plants, by D. T. MacDougal. Paper, 16 pp. - - .30 



THE PLANT WORLD TUCSON, ARIZONA 



Pans for Retaining Power of Soils 



The results of different workers can ba made comparable by the use 

 of uniform pans and a uniform method for the determination of the 

 maximum water-retaining power of soils. The pans here shown are 

 of heavy copper sheet, with perforated bottom and with wall 1 cm. 

 high. They are 11.5 cm. in diameter and hold approximately 100 

 cc. of soil, an amount small enough for easy handling and large 

 enough to avoid serious errors in weighing. A circle of thin filter 

 paper should be placed in the bottom. See Hilgard's "Soils," p. 209. 



Each $1.25; Per Ten $10.00 



The Plant World 



Tucson, Arizona 



THE BELLANI PLATE 



The Bellani Plate is a new type of Atmome- 

 ter presenting a flat horizontal evaporating sur- 

 face 7.5 cm. in diameter, attached to a glazed 

 hemispherical funnel. These instruments are 

 calibrated to a standard plate of the same type. 

 As compared with a free water surface this Plate 

 presents all the advantages of a fixed and un- 

 changing evaporating surface which is not liable 

 to accidental disturbance. 



Each $2.00 Per Ten $18.00 



THE PLANT WORLD TUCSON, ARIZONA 



