soils FERTILIZERS. 13 



It was found '• that the precipitation of calcium carbonate is substantially the same 

 in each case, while the precipitation of magnesium carbonate is increased by the 

 difference between 8.52 and 4.61, or 3.91 by the greater pressure. Boiling for 20 

 minutes at the normal pressure removes 1 1 per cent of the temporary hardness; thai 

 is, the calcium and magnesium carbonates. At the increased pressure, 63.5 per cent 

 is removed. 'The water, therefore, can not be said to be softened l>\ either process. 

 It was found . . . that <>n treating the raw water with lime water in the ratio of 6 

 to l. 71.42 per cenl of the temporary hardness was removed." 



A study of the underground waters of the region of Cadereita Mendez, 

 State of Qaieretaro, .1. de I >. Villarello I Bol. Sec. Fbmento [Mexico], ;. ser., 4 

 [iuu:>), Propaganda No., Pamphlet 18, j>/>. 5-65). 



SOILS FERTILIZERS. 



Investigations in soil management, F. II. King {('. S. Dept. Agr., Bur. Soils 

 Unl. 96, />/>. .'0~>. ph. 4,figs. 9). — The three papers included in this bulletin belong 

 to a scries of (i papers constituting the report of the Chief of the Division of Soil 

 Management of the Bureau of Soils for 1902 and L903. The other three papers of 

 tin' series were published privately by the author, and have already been noted 

 (E. s. R., lt>, p. 546). In recommending the papers for publication, the Chief of 

 the Bureau of Soils explains that the Bureau assumes no responsibility for the 

 opinion- ami conclusions they contain. 



/. — Amount of plant food readily recoverable from field soils with distilled water (pp. KI- 

 TS, li-j-s. ."»). — This paper reports ami discusses "the results of two seasons' investiga- 

 tions relating to the amounts of plant-food materials and other water-soluble salts 

 which could he recovered from different soil types and from the same soil types 

 under different conditions by bringing them into contact with distilled water for a 

 very brief period only." The more important soil types in a number of the areas 

 surveyed by the Bureau of Soils in Georgia, Maryland, New .Jersey. North Carolina, 

 Pennsylvania, Smith Carolina, Virginia, and Wisconsin were studied. "One of the 

 most important objects of these investigations was to ascertain what relation, if any, 

 exists between the character ami amounts of the water-soluble salts present in a -oil 

 and the yield and quality of crop matured upon it at the same time. In planning 

 and executing those studies the work was so shaped that as far as possible the inves- 

 tigations should he made in direct connection with some crop or crops whose yields 

 could he definitely ascertained and whose growth was under observation." 



Earlier investigations along the same line are reviewed. The methods of taking 

 soil samples and preparing the soil and plant extracts are described. "In preparing 

 the soil extract the cores of the soil sample were well broken down and thoroughly 

 mixed in a granite-ware basin. Two I00-gm. samples were then weighed out on a 

 Springer'torsion balance, one being transferred to a Wedgwood mortar and the other 

 to the dry oven for moisture determinations. In a graduated flask 500 cc of dis- 

 tilled water were measured out, and ( nough was added to the sample in the mortar 

 to work it into a thick paste with the pestle, breaking down the granulations, when 

 the balance of the water was added and the whole stirred continuously with the pes- 

 tle during ?> minutes. The supernatant turhid liquid was then transferred to a pint 

 .Mason jar and from here, usually inside of 15 minutes, to the lilter chambers. . . . 

 By means of compressed air in the reservoir the solutions were filtered, under a 

 pressure of about 30 to 40 lbs., through Chamberland-Pasteur filters, and perfectly 



clear extracts obtained in from 5 to -I) minutes, depending upon the character of the 



soil or the amount of fine sediment remaining suspended in the solution to he depos- 

 ited upon the walls of the filters. . . . 



"In the preparation of plant extracts for the work hoe reported the samples were 

 always taken at the places where the soil samples were procured, and at the same 



