SOILS FERTILTZEES. 1023 



11k' past eight or ten years has been that they keep on the jiround too long — 

 lliat is, malve but little upward growth until the warmer weather sets in. and 

 tlien too often before they mature their grain they arc caught with hot winds. 

 On the other hand, except in the coldest districts, our ordinai-y wheats make con- 

 siderable growth before the spring sets in, and tiius have more prospect of 

 maturing their grain." 



The weather maps of the public weather service, (Ikohaiann (Siiclis. 

 LaiKla: Ztschr., o) (1006), .To. 50, pp. ISOo-lSlO, pjs. .?).— The character and 

 use of the weather maps issued by the (ierman weather service are explained. 



Weather predictions, Jochimskn {lAUidir. Wchiibl. Hclilcs. Hoist.. .57 (1901), 

 iAci.s'. 10. pp. l.il-l-i!>: 11, pp. I.'i9-152). — Brief explanations of weather predic- 

 tions and their utilization in agi'iculture are given. 



On purification of sewage waters, A. Muntz and K. Laink (Coiiipt. Rend. 

 Acad. .s'c/. [Paris]. l','i ( HuH). \<,. <). pp. 7/60-470) -—Experiments with filters of 

 peat are reported which tend to show tiiat it is possible by jiroper manipulation 

 of this material to increase enoniuiusly the purification capacity of bacterial 

 filter beds. 



Nitrification of sewage, G, Retd (Proc. Roi/. Hoc. [Litiiddii], 8cr. B. 19 

 (1901). Xo. B 528, pp. 5S-1J,, fu/.s. 2; Jour. Roy. miu lust., 28 (1901), Xo. 3, pp. 

 1 'i2-l-'i9). — This iiaper reports the residts of observations on the influence of the 

 deiith of filters and the size of i)articles on the efliciency of the purification. By 

 means of shallow trays with perforated covei's placed at 1 ft. intervals in a 

 lilt(>r bed composed of J-in. particles, studies were made of the progress of nitri- 

 lication in the sewage at different depths. The results show that the nitrifica- 

 tion took i)Iace very largely in the first 12 in. of the filter, and indicate that in 

 general the efficiency of a filter is to be increased by extending its area and by 

 using finer particles rather than by increasing its depth. 



The bacterial treatment of sewage, W. D. Scott-Moncrteff (Surveyor, 31 

 (1901). Xo. 190. pp. .«/-.«.?. fii/s. 2; Jour. Roy. San. Inst., 28 (1901), Xo. 3, pp. 

 111-1 'it, /iys. 5). — Experiments similar to those recorded in the preceding article 

 and with like results are reported. 



SOILS— FERTILIZERS. 



A review of the geographical and geological conditions of Alaska, A. 

 lU'iiL (Mitt. Justus Perthes' (leoyr. Aust., 53 (1901). Xo. 1, pj). 1-16, )nap 1). — 

 The general geology, hydrography, and climate are briefly i-eviewed. A colored 

 map based upon that of E. (". Barnard, of the U. S. Geological Survey, illus- 

 ti-ates the main features of the present knowledge of the physical geography of 

 Alaska. 



The agricultural-bacteriological examination of soils, U. 1'krotti (.1/// R. 

 Aecad. Lincel, Rend. CI. Sci. Fis. Mat. e Nat.. 5. ser.. Ul (1901). J, Xo. 1. pp. 

 (11-15). — The author briefly reviews a number of the more imiiortant reports of 

 investigation on this subject and reports a series of studies of the growth of 

 soil organisms in a medium consisting mainly of an extract of peat in com- 

 I>arison with other standard culture media. 



The peat extract was prepared by boiling 100 gm. of air-dry peat over a 

 direct flame for 2 hours with 500 cc. of water and digesting another 100 gm. 

 l'(ir 2 hours in an autoclave at 120° with 500 cc. of water, filtering, and com- 

 bining the extracts. For use as a culture medium the e.xtract was diluted until 

 it contained about 1 per cent of mineral matter. This solution h;i<l a slightly 

 acid reaction. Both the acid solution and that which had been made slightly 

 .ilkaline were used in the experiments reported. The growth of micro-organisms 

 was much more rai)id in the alkaline extract to which glucose had been added 



