Jandary 2, 1903.] 



SCIENCE. 



29 



'Artificial Plant Food Eequirements of 

 Soils,' by B. W. Kilgore. (See ' Proceedings 

 of the Fifteenth Annual Convention of the 

 Association of American Colleges and Experi- 

 ment Stations,' pp. 73-75.) 



' Methods for the Determination of Total 

 Phosphoric Acid and Potash in Solids,' by 0. 

 B. Williams. 



The method devised for the determination 

 of total phosphoric acid in soils was simply, 

 after igniting five grams of soil in a platinum 

 dish, treat three times with hydrofluoric acid, 

 evaporating to dryness each time, followed 

 by fusion with ten grams of a mixture of 

 equal parts of sodium and potassium car- 

 bonate. The cake thus obtained, after cool- 

 ing, was transferred to a beaker and digested 

 with about 30 to 40 c.c. (1 to 1) hydrochloric 

 acid, after which the solution was evaporated 

 to dryness on a water-bath, being subsequently 

 heated four or five hours in an air-bath, to 

 110° C. to dehydrate the silica present. It was 

 then taken up with dilute hydrochloric acid, 

 filtered and washed. The filtrate and wash- 

 ings thus obtained, after adding sufficient 

 nitric acid to liberate all hydrochloric acid 

 present, are placed together and reduced to a 

 volume of about 40 c.c. by boiling. The excess 

 of nitric acid is then neutralized with am- 

 monia, and ten to twelve grams ammonium 

 nitrate is added. After cooling, 30 c.c. re- 

 cently fi[ltered molybdic solution is added 

 and the phosphoric acid is precipitated by 

 shaking in a Wagner machine, and determined 

 volumetrically {Jour. Am. Chem. Sc, Vol. 23, 

 No. 1, pp. 8-12). 



Total potash is brought into solution by 

 treating four grams of soil in a platinum dish 

 on water-bath, after saturating with dilute (1 

 to 1) sulphuric acid and igniting, with from 2 

 to 3 c.c. hydrofluoric acid for five times, add- 

 ing 1 c.c. dilute (1 to 1) sulphuric acid just 

 before going to dryness the last time. After 

 the last traces of hydrofluoric acid have been 

 liberated the dish is removed from water-bath 

 and heated gently over small flame until evo- 

 lution of sulphur trioxide ceases. The soil 

 is then taken up with 20 c.c. distilled water 

 slightly acidified with hydrochloric acid, and 



digested on water-bath until the solution has 

 been reduced to about one third of its orginal 

 volume, after which it is transferred to a 

 200-c.c. graduated flask and heated on water- 

 bath to near boiling, when ammonia and am- 

 monium oxalate are added in sufficient quan- 

 tity to precipitate all iron, alumina and lime 

 present. After cooling, the volume is made 

 up to 200 c.c, and an aliquot corresponding 

 to two grams is filtered off into a porcelain 

 dish. Prom this point on the procedure is 

 the same as that prescribed in the regular 

 Lindo-Gladding method. 



There being no further business, the sec- 

 tion adjourned, subject to the call of the 

 Executive Committee. 



C. B. Williams. 

 Secretary. 



DISCUSSION AND CORRESPONDENCE. 



PRESIDENT SCHURMAN ON THE EDUCATIONAL EE- 

 QUIREMENTS FOR PROFESSIONAL STUDY. 



To THE Editor op Science: In the issue of 

 Science of November 21, on page 816, is pub- 

 lished an excerpt from the annual report of 

 President Schurman of Cornell University, 

 containing statements bearing upon the ques- 

 tion of collegiate work as a requirement for 

 admission to professional schools. It is 

 not my function to discuss or criticize the 

 policy of the President of Cornell University. 

 The report, however, contains several state- 

 ments upon which comment seems necessary. 



" At Cornell University at any rate [runs 

 the report] the established policy is to admit 

 students to any course who are able to pass 

 the examinations qualifying them to pursue 

 that course. And such preliminary tests, it 

 is generally conceded by the members of the 

 profession concerned, do not exceed the re- 

 quirements for graduation at the best high 

 schools." 



I cannot speak for the lawyer, the engineer 

 or the architect, but in the name of the pro- 

 fession of medicine I beg in the most respect- 

 ful manner to protest. With the matter of 

 culture-studies we need have no concern here. 

 I believe it may be stated as an established 

 fact that a proper education in modem 



