538 Physiologie. 



the capillary pull of soils. (Plant World XVIII. p. 11 — 13. 

 1915.) 



Description of a simple apparatus for determining by means of 

 a manometer the capillary pull of soils. While the author acknow- 

 ledges that this method shares with the method ofdirect Observation 

 of capillary rise of water in soil the errors due to inevitable diffe- 

 rences between soils, even of the same kind, as regards compactness, 

 he believes that such errors can be minimized by repeated tests, 

 which are easil}^ made by this method. Sam. F. Trelease. 



Livingston, B, E., A modification ofiheBellaniporous 

 plate atmometer. (Science, N. S. XLI. p. 872-874. f. 1. 1915.) 



Description of the author's recently devised modification of the 

 Bellani atmometer for measuring evaporation, with a discussion 

 of the kinds of studies in which it is to be employed. The apparatus 

 consists of a circular porous clay plate mounted across the large 

 end of a glazed porcelain funnel. In Operation, the opening in the 

 apparatus is closed by a rubber stopper bearing a glass tube reaching 

 to a water reservoir below, the mounting being the same as that 

 of the author's ordinary cylindrical porous cup. It is said to be 

 particularly useful in climatological and meteorological studies in 

 which an Instrument having a plane evaporating surface is to be 

 employed. The Instrument possesses the advantages of a free water 

 surface, without its disadvantages, such as errors from wave action 

 caused by wind, splashing, removal of water b}'^ animals, and the 

 capture of animals, etc. In addition it has all of the advantages of 

 the porous cup atmometer, including non rain-absorbing mounting 

 and ease of accurate readings at short intervals either in terms of 

 volume or weight. Sam F. Trelease. 



Livingston, B. E., Atmometry and the porous cup atmo- 

 meter. (Plant World. XVIII. p. 21-30, 51—74, 95—111, 143—149. 

 f. 1 — 8. 1915. Also reprinted coUectively Tucson, Arizona, 1915.) 



A series of papers bringing together the essential points as far 

 as they have been worked out concerning the manipulation of 

 atmometers, used for measuring evaporation, particularl}^ in studies 

 of plant and animal environment, and the interpretation af atmo- 

 metric readings. In a discussion of atmospheric evaporating power 

 and its measurment in general, the author emphasizes the fact that 

 the kind of water surface used (including size, form, material, etc., 

 of Container) is as truly a control of the rate of water loss as are 

 the atmospheric conditions, and that similar instruments must be 

 used for comparable results. It is pointed out that readings obtained, 

 for varying environmental conditions, from one kind of Instrument 

 cannot be reduced with accuracy to those obtained from another 

 kind of instrument. Among the atmometers described are the open 

 pan, the P.iche, the Pic he-Can ton i, the Pickering, the paper 

 cylinder, the Bellani porous plate, and the Livingston porous 

 clay cup. It is this last instrument, of the cylindrical form, which 

 receives most attention in this series. Among the advantages men- 

 tioned for porous surfaces, as contrasted with the open pan, are 

 freedom from wave action by the wind, facility of arrangement so 

 as to give small readings in terms of eiiher volume or weight, and 

 exposure of the evaporating surface in much the same manner as 



