118 EXPERIMENT STATION" RECORD. 



of Pressure in tlie Atmosphere Recorded by au Interferometer Barograph 

 (illus.), by A. C. Crehore and G. C. Squier; The Amount and Vertical Dis- 

 tribution of Water A^apor on Clear Days (illus.), by W. J. Humphreys; The 

 Earth's Radiation Zones (illus.), by W. J. Humphreys; The Height and Tem- 

 perature of the Isothermal Region at Different Latitudes and under Different 

 Conditions, by W. J. Humphreys; Meteorological Photographs, by C. F. Talman ; 

 and Free Air Data, at Mount Weather, for April, May, and June, 1911 (illus.), 

 by W. R. Blair. 



The ag-ricultural zones of the Tropics in their relation to climate, W. R. 

 EcKAEDT {Tropenpflanzer, BeiJiefte, 12 {1911), No. 5, pp. 399-508) .—This article 

 is intended as an introduction to succeeding articles to be based on the author's 

 own studies and gives a detailed review of the literature of the subject, includ- 

 ing the influence of climate on the soil, plant and animal life, and agriculture 

 of the Tropics, and a climatic classification on the basis of vegetation, more 

 particularly cultivated plants. 



The rains of the Nile Basin and the Nile flood of 1909, J. I. Ceaig (Survey 

 Dept., Egypt, Paper 17, pp. 55+III, pis. 9). — Observations similar to those 

 of previous years (E. S. R., 23, p. 312) are recorded in this report. 



The author is of the opinion, as a result of his studies, that within a few 

 years the prediction of the main features of the Nile flood " may be embodied 

 in an algebraic formula such as has already been obtained for the Indian mon- 

 soon by Mr. G. T. Walker. . . . The rainfall in Abyssinia during the flood 

 months is due almost entirely to the precipitation caused by diurnal ascensional 

 movements acting on the southwesterly current which again is kept at the 

 point of saturation by its ascent on to the Abyssinian tableland." The course of 

 the latter has been pretty clearly traced across the African continent to the 

 South Atlantic. 



[Water analyses, 1910], R. E. Rose (Fla. Quart. Bui. Dept. Agr., 21 {1911), 

 No. 1, pp. 139-166). — Partial and complete mineral analyses of a large number 

 of samples of water from different parts of the State are reported. 



The drying of sludge, F. Spillner (Mitt. E. Priifungsanst. Wasserver. tl. 

 Al)icasser. Berlin, 1911, No. IJ^, pp. 27-84, figs. 8; al)S. in Engin. and Contract., 

 36 (.1911), No. 12, pp. 303-307; Wasser u. Aiwasser, 4 {1911), No. 9, r>p. 382, 

 3S3). — It is pointed out that the most important problem in connection with 

 sludge disposal is the removal of the excess of water. Various processes which 

 have been proposed for this purpose are described. Analyses are given of wet 

 and dry sludge prepared by the so-called Emscherbrunnen process. According 

 to these analyses the water in this sludge varied from 75 to 80 per cent, the dry 

 sludge containing from 1.1 to 1.56 per cent of nitrogen. 



It was found in experiments with sludge prepared by different processes that 

 septic tank sludge which had undergone considerable decomposition furnished 

 a product which was most easily dried and put in condition for subsequent 

 handling as a fertilizer, fuel, etc. 



SOILS— FERTILIZERS. 



Soil surveys for agricultural purposes, A. D. Hall and E. J. Russell (Rpt. 

 Brit. Assoc. Adv. ScL, 1910, 2)''585). — It is stated that "the object of a soil sur- 

 vey is to give an account of the soils of an area in their relation to the local 

 agriculture. The methods adopted must be such that it is possible (1) to 

 classify together soils of the same formation which have similar agricultural 

 properties, and differentiate between others with dissimilar properties; (2) to 

 bring out clearly and unmistakably any connection that may exist between 

 type of soil and special crops or special agricultural methods; (3) to afford 



