SCIENCE. 



ate methods used in the investigations of 

 ous soil extracts.* Moreover, the amounts 

 .e several substances contained in the soil 

 .cts, present in the sap of the plants them- 

 s, were likewise determined, in order to 

 tain the relations between the soil solu- 



and the substances taken up by the crops, 

 is not easy for the outsider to detect any- 

 f reprehensible in this well-considered 

 of operations. It seems to be admirably 

 jived for the determination of the relation 

 le soil solutions to plant nutrition and 

 production under normal, practical condi- 

 . The details given regarding the actual 

 ing out of the experiments are equally 

 ceptionable, except as concerns some 

 ;s in respect to which, apparently, there 

 interference of some sort with the plan; 



in the matter of making chemical anal- 

 of the stable manure used at the several 

 ities. But however regrettable, this and 



other omissions, apparently imposed by 

 ior authority, do not vitiate, to any ma- 

 l extent, the conclusions arrived at by 



e plan and methods of experimentation 

 f thus unexceptionable so far as any one 

 ining the record given can judge, the only 

 ion remaining is 'whether the conclusions 

 sed from the experimental results are 

 fled, and whether these are in conflict with 

 ical or scientific experience, or with corn- 

 sense. Of these conclusions it will be 

 to give the chief ones in the words of the 

 >r. 



ter giving, on page 5, a table showing the 

 mtage relations of crop yield under dif- 

 t fertilizations, he says : ' It will be seen 

 in the case of the poorer soils there is a 

 ntage difference of 46 between the yields 

 e fifteen-ton subplots and those to which 

 ng has been added; but a difference of 

 eighteen on the stronger soils/ Recal- 

 ing these results on the next page so as to 

 their relations more clearly, he adds: 

 se results show that both relatively and 

 utely, adding fertilizers to the poorer soils 

 lad a greater effect than the same treat- 

 iulletin No. 22. Bureau of Soils. 



ment with stronger soils.' Farther on, 

 giving a table of the several yields of V 

 free shelled corn, he says : " It is here seen 

 on the four poorer soils, there is a systei 

 difference in the yield of water-free si 

 corn, closely related to the fertilizers ap 

 to the soil. The group of four stronger 

 do not show, throughout, this systematic 

 tion." Photographic views of the corn o: 

 growing plots show these differences clear 

 the growth of the plants. 



The only criticism that could be, per 

 made of the work leading to these conclu 

 from an outside point of view, is that 

 are so clearly and thoroughly in accord 

 all former experience, both practical am 

 peri mental, that they are largely foresee: 



Then follows the record and discussic 

 corresponding experiments with pot* 

 which yield practically the same results 

 conclusions. 



Then are given the results of analysi 

 leachings of the same soils upon which 

 crops had been grown. The results are 

 sented in a table, from which " it is very 

 that the effect of different amounts of s 

 manure applied to these soils * * * has 

 such upon the recovery of the water-so 

 salts as to enable the same treatment t 

 move different amounts from different fe 

 zations. * * * There is a clear quantit 

 relation, too, between the yields and the 

 recovered, these (the former) incres 

 where the essential ingredients of plant 

 are higher." 



King also details the experiments i 

 with small (four-pound) samples of soils n 

 with much larger amounts of the same ma: 

 the leachings of which after 65 days, i 

 in general, results corresponding to thosi 

 tained from the field tests ; and he discuss 

 detail the apparent effects upon the solubi 

 of the several ingredients of plant food, 

 the influence upon the formation and redu< 

 of nitrates; showing that there is no d 

 ratio between the amount of manure a 

 and the nitrates found in the different ! 

 He determines and discusses, likewise, th 

 lation of the salts added to the soils in 



