SOILS FERTILIZERS. 723 



The crumby superphosphate (crumbs 2 mm. in diameter with gypsum and 

 larger with agar) was never less effective than the fine-ground, and in certain 

 cases was more effective. Depth of application had more effect than crumb- 

 ing. On the other hand, crumbing of Thomas slag reduced the effectiveness of 

 the phosphoric acid. 



Accessory constituents of phosphatic slag-, A. Dp:molon and G. Broukt 

 (Jour. Agr. Prot., n. scr., 21 {191.',), No. 1, pp. 22, 25).— Analy.ses are reported 

 showing on the average about 4 to 5 per cent of manganese, a considerable pro- 

 portion of which was soluble in 2 per cent citric and acetic acids. The mag- 

 nesia content was variable but on the average about 10 per cent. The free lime 

 varied from 8 to 10 per cent. 



It is suggested that the fertilizing effect of sl;ig may be due in part to the 

 manganese and magnesia which are present to a large extent in available form. 



A brief note on the phosphate deposits of Egypt, J. Ball (Survey Dept. 

 Egypt Paper 30 (1913), pp. 6, pi. 1). — Phosphate deposits occurring in seven 

 different localities in the deserts of Egypt in the sedimentary strata belonging 

 to the uppermost part of the Cretaceous system are briefly described. 



Phosphate deposits were discovered in Egypt in 1900, and their exploitation 

 began in 190S. The output in 1012 was .69,958 tons, mainly from the SafAga 

 and Sibaia districts. 



Topography and g-eolog-y of the phosphate district of Safag-a, J. Ball 

 (Survey Dept. Egypt Paper 29 (1913), pp. 19, pis. J,, fig. J).— The topography 

 and geology of this district, which contains the phosphate deposits which are at 

 present of most importance commercially in Egj^pt, are fully described. 



" The phosphatic series consists of laminated gray clays with beds of calcium 

 phosphate and chert, lying below the Upper Cretaceous limestones and above 

 the Nubian sandstone. The total thickness of the series is about 4.') meters, of 

 which clays occupy about three-fourths. The phosphate beds occur in the 

 upper part of the series. There are three principal bods of phosphate. . . . TTie 

 beds vary somewhat in thickness and composition from point to point. . . . The 

 highest bed of the series, . . . which has an average thickness of about 1.8 

 meters and contains in places as much as GO per cent of tricalcic phosphate, 

 immediately underlies the Cretaceous limestone, which latter is sometimes 

 marly at its base. Then follows about 5 meters of brown chert beds, with thin 

 bands of hard siliceous phosphate and occasionally thin clay partings. Imme- 

 diately below the chert comes [the second] phosjihate bed, with a thickness 

 of about 1.3 meters and 50 to 75 per cent of tricalcic phosphate. This is followed 

 by some 9 meters of gray and brown laminated clays, separating it from [the 

 third] phosphate bed, which averages about 2 meters in thickness and contains 

 20 to 45 per cent of tricalcic phosphate. Below [this] phosphate bed the gray 

 and brown laminated clays extend down for some 25 meters to the Nubian 

 sandstone. 



" In general appearance the phosphate somewhat resembles an earthy looking 

 limestone or calcareous grit. It is a friable rock of a pale brown color with 

 white spots, made up largely of phosphatic grit with a fair sprinkling of broken 

 up fish bones, coprolites, and teeth. Where it is weathered on exposed faces 

 the phosphate is typically of a darker color than on a fresh fracture, and the 

 harder coprolites in it stand out as black six)ts. giving it a characteristic 

 speckled appearance, which, though difficult to describe, is readily recognized 

 when once seen. ... It is generally found that tlie more friable varieties are 

 the richest, yielding over 70 per cent of calcium phosphate. The top of [the 

 second] seam Is frequently formed of a hard variety of the rock, called ' hard 

 panel ' by the miners, containing only some 50 per cent or so of phosphate; this 

 44429°— No. 8—14 3 



