116 



Bui. 107), shaking thoroughly. The solution should be kept at 40 or 50 C. for 

 an hour, then let stand overnight at the room temperature, filter, and wash well 

 with cold water. A Hirsch funnel with a double qualitative filter, S and S No. 597, 

 cut to fit, and well pressed down around the edge with the finger after wetting and 

 putting on pressure, is recommended. Put filter and precipitate back into the same 

 flask, using as little water as possible for washing back into flask. Determine phos- 

 phorus volumetrically, using standard potassium hydroxid and nitric acid. 



(d) Fuse 1 gram of soil according to the well known J. Lawrence Smith method. 

 Transfer the fused mass to a porcelain dish, slake with hot water, grind finely with 

 an agate pestle, and transfer to a filter. After washing free of chlorids, concentrate 

 the filtrate and washings in a Jena beaker to about 20 cc, and filter. Slightly acidify 

 the filtrate and washings with hydrochloric acid, concentrate in a platinum dish, 

 add 1.5 cc of a platinic chlorid solution (10 cc contains 1 gram of platinum). Evapo- 

 rate to a sirupy consistency, as usual, and wash with 80 per cent alcohol and ammonium 

 chlorid solution. 



(e) Determine potassium according to the regular J. Lawrence Smith method." 



The referee inclosed with his instructions to those who expressed a willingness 

 to cooperate in the work a short personal letter, and had hoped that each one would 

 contribute something to this report, but unfortunately, as it often happens, manv 

 were not able to send in results in time for use. The referee desires to express his 

 thanks to the following chemists who have aided him in the work: A. W. Gregory, for 

 the Illinois station; W. P. Kelly, for the Hawaii station; P. E. Brown, for the New 

 Jersey station; G. S. Fraps, for the Texas station; W. B. Ellett, for the Virginia station; 

 I. O. Schaub, for the Iowa station; and P. F. Trowbridge, for the Missouri station. 



It will be seen from Table 1 that the results obtained by the sodium peroxid fusion 

 and the magnesium nitrate method show practically no difference. One chemist 

 gets results in Soil II somewhat higher than the others, but the amounts of phos- 

 phorus obtained by the two methods on three determinations are almost identical. 

 In Soil I, with the exception of one determination, the maximum and minimum 

 results are not bad duplicates. 



a Fresenius's Quantitative Chemical Analysis, p. 426. 



