May 27, 1904.] 



SCIENCE. 



835 



nated between litmus paper moistened with 

 distilled water. The acid tracings of the roots 

 were distinct, and there were no soil solutions 

 charged with carbon dioxide present. 



A critical examination of the data given in 

 Bulletin No. 22 shows that the conclusion is 

 not consistent with the figures. To illustrate : 

 On page 32 it is stated that a wheat field 

 yielding 35 bushels per acre contained 2.49 

 parts of POj per million parts of air-dry soil. 

 The most liberal calculations show less than 

 five pounds per acre foot of water-soluble 

 phosphoric acid; accepting the data given as 

 correct, a wheat crop of 35 bushels would 

 remove 40 pounds at least of phosphoric acid. 

 In other words, all of the water-soluble phos- 

 phoric acid in this soil to a depth of eight 

 feet by pure physical action alone would not 

 supply this crop with food. To assume that 

 all the water-soluble plant food can possibly 

 be utilized to a depth of eight feet is even 

 an incorrect assumption, because Hellriegel's 

 experiments show conclusively that there is a 

 limit to the capacity of crops for absorbing 

 water. 



To assume that a selective process takes 

 place based on physical properties alone and 

 that the plant has the power to take up more 

 water-soluble phosphoric acid than water in 

 which it is dissolved independent of chem- 

 ical action or solvent power is not correct. 

 Because if such a purely physical action- were 

 to take place, the ions of lime, magnesia, etc., 

 forced back into the solution by the with- 

 drawal of the PO^ ions would make the re- 

 maining phosphoric acid less soluble. In fact, 

 purely physical action based upon ionization, 

 as claimed by the authors, would be working 

 against the plant instead of aiding it in se- 

 curing plant food. 



Most of the data given in Bulletin No. 22 

 point to just the opposite conclusions from 

 those drawn. It is stated that there are no 

 material differences in the amounts of water- 

 soluble plant food present in soils producing 

 the largest and the smallest crop yields. The 

 figures in the bulletin conclusively show that 

 on a purely physical basis the rich soils do 

 not contain enough water-soluble plant food 

 to account for all of the mineral matter found 



in the crop. There is only one alternative, 

 namely, since the figures show that there is 

 not enough water-soluble plant food to ac- 

 count for all that there is present in the crop, 

 it must be derived from other and insoluble 

 forms. In fact, no better evidence could be 

 given showing such a conclusion to be logical 

 than the tables in Bulletin No. 22. In short, 

 the conclusions are entirely at variance with 

 the tables. Haert Snyder. 



Ageicultueal Expeeiment Station, 

 St. Anthony Paek, Minn. 



TUE EDISON MEDAL. 



Through the efforts of an organization 

 known as the Edison Medal Association, a 

 fund has been created to establish a medal to 

 be known as the ' Edison Medal,' and the re- 

 sponsibility of annually awarding it has been 

 entrusted to the American Institute of Elec- 

 trical Engineers. 



The Edison Medal Association was founded 

 by the friends and admirers of the great in- 

 ventor, and in the language of the deed of 

 gift, ' was organized for the purpose of prop- 

 erly recounting and celebrating the achieve- 

 ments of a quarter of a century in the art of 

 electric lighting, with which the name of 

 Thomas Alva Edison is imperishably identi- 

 fied,' and ' for the establishment of an Edison 

 Medal, which should, during centuries to come, 

 serve as an honorable incentive to the youth 

 of America to maintain by their works the 

 high standard of accomplishment by the illus- 

 trious man whose name and features shall 

 live while human intelligence continues to 

 inhabit the world.' 



The gift was formally made, and the re- 

 sponsibility of conferring it assumed by the 

 institute at its annual dinner given at the 

 Waldorf-Astoria Hotel in New York, on 

 February 11 last, held to not only commem- 

 orate the event, but also to celebrate the fifty- 

 seventh anniversary of Mr. Edison's birth. 



The fund has been deposited with the Con- 

 tinental Trust Company of New York, and 

 there will be available this year sufficient 

 funds for a medal, which will be awarded by a 

 suitable com.mittee of the institute, soon to 

 be appointed. 



