WATEE — SOILS. 125 



WATER— SOILS. 



The sig-nificance of phosphates in natural waters, A. G. Woodman {Jour. 

 Amer. Chern. Soc, 34 {1903), No. 8, ])}). 735-743).— It is claimed that the determina- 

 tion of phosphoric acid in natural waters ' ' by reason of the conversion of organic 

 phosphorus compounds into phosphates through the processes of decay is one which 

 might reasonably be expected to throw considerable light on the question of the 

 p illution of [such] waters." The author has used with success a modification of 

 J. West-Knights'^ method, evaporating 50 cc. of the water and 3 cc. of nitric acid 

 (si3. gr. 1.07) to dryness on a water bath, and heating the residue in a water oven 

 for 2 hours. The dry residue is taken up in 50 cc. of cold distilled water, 4 cc. of 

 ammonium molybdate (50 gm. per liter) , and 2 cc. of nitric acid added, and the color 

 comi)ared with standards made by diluting varying quantities of a standard phos- 

 phate solution (1 cc. =0.0001 gm. phosphorus pentoxid) to 50 cc, and adding the 

 reagents as above. Blank determinations on the distilled water are advised. 



Determinations in a large number of samples of water are reported, together with 

 data obtained by the ordinary sanitary analysis of water. These data show that 

 "the amount of phosphate and its variation seem to follow the same general line as 

 the other mineral constituents which either accompany the polluting material or are 

 produced by its decay, especially the nitrates and the chlorids. It is not, however, 

 so delicate an indicator as these. . . . The results obtained by the colorimetric 

 method would seem to indicate that the limit of 0.5 part of phosphorus pentoxid in 

 a million, as given by Hehner for unpolluted waters, is rather low. A safer amount 

 would be 1 part, although the average would doubtless be lower than this." 



Artesian waters and irrigation, W. G. Cox {Agr. Jour. Oipe Good Hope, 30 

 {1903), No. 11, pp. 613-618). — This article gives data relating to artesian borings in 

 Queensland, with a discussion of the influence of artesian irrigation on the agricul- 

 ture of that region. 



Well waters from farm homesteads, F. T. Shutt {Canada Expt. Farms 

 RpU. 1901, pp. 193-196). — Analyses of 61 samples of water with reference to sanitary 

 condition are reported. 



Some excessively saline Indian well waters, J. W. Leather {Jour. C'Jiem. Soc. 

 [London], 81 {1903), No. 476, 1, pp. 887-893) .—Analyses of a number of such waters 

 are reported and their use in irrigation is l^riefly discussed. 



The examination of water from some typhoid-polluted wells, S. Rideal 

 {Anah/st, 37 {1903), No. 317, pp. 345-347). 



The temperature of the soil, D. T. MacDougal {Jour. New York Bot. Gard., 3 

 {1903), No. 31, p)p. 135-131, figs. 3). — A description is given of a thermograph devised 

 by Prof. W. Hallock, of Columbia University, for making a continuous record of the 

 temperature of the soil at any desired depth. "The essential features of the Hallock 

 thermograph are as follows: The thermal element of the instrument consists of a 

 copper bulb or globe 11 cm. in diameter, with a strengthening equatorial ridge, filled 

 with commercial kerosene. A short section of copper tubing with a heavy wall is 

 soldered to an opening in one pole of the globe, and the free end of the heavy tube 

 receives a small copper tube with an external diameter of about 4 mm. , a bore of 1 mm., 

 and of any desired length. The tube is also filled with petroleum. The free end of 

 the small tube is connected with a chamber consisting of a pair of corrugated brass 

 disks 8 cm. in diameter, with the edges soldered together. The chamber is seated 

 on a metal block fastened to the base of a recording apparatus and the tube connects 

 with the chamber through an opening in the metal block. An ojiening is made in 

 the upper side of the first chamber and a second chamber of the same kind is sol- 



^ Analyst, 5 (1880), p. 197. 

 8994— No. 2—02 3 



