from Washington Territory. 245 



It is worth while to inspect these data a little more closely. 



We -have found, for instance, that the soil yields to hydro- 

 chloric acid 2*50 per cent sodium and potassium chlorides 

 (=•78 per cent K 2 + -67 per cent Na 2 0). We have further 

 found by mechanical analysis that the silt and the clay, those 

 fractions from which, owing to their fineness, the plant-roots 

 most probably derive their food, form only about one-third 

 part of the soil (31*84 per cent). We have also seen that the 

 other two-thirds, which consists of coarse sediments, yielded 

 absolutely and relatively much larger quantities of alkalies to 

 hydrochloric acid than the finer sediments. The 2*50 per cent 

 of alkali-chlorides found in the entire soil have therefore to be 

 divided at least by four or five in order to give us ' an idea of 

 the available plant-food, which even then is very uncertain. 

 Exactly the same reasoning can be applied to the alkaline 

 earths. 



Speaking about soils, Professor Storer says in his text-book, 

 " Agriculture in some of its relations with chemistry," vol. i, 

 p. 199 . " With the exception perhaps of midwinter, when 

 everything is frozen stiff, it is certain that chemical changes 

 are constantly occurring in every soil. From the chemical 

 point of view nothing like rest can be conceived of in a mix- 

 ture so complex as the loam of an ordinary field." 



Considering again the results above discussed, I should like 

 to add that to produce a " mixture so complex " nature has to 

 work many thousand years ; it seems to me, therefore, to be a 

 vain attempt to force an answer from a soil by a single analysis 

 as to its fertility, which is the result of the coincidence of nu- 

 merous factors, of which some, and probably many, are so 

 occult as to escape our direct observation. Among the favor- 

 able conditions which determine the fertility of a soil must be 

 classed, 



The distribution of the phosphoric acid. 



My analyses show that the sediments <-25 mm h. v. contain 

 the largest amount of phosphoric acid (*42 per cent). With 

 what bases is the phosphoric acid in the silt and in the other 

 sediments combined ? 



In order to answer this question approximately I made use 

 of the different behavior of the phosphates of iron, aluminum, 

 and calcium toward dilute acetic acid, in which both the first- 

 mentioned phosphates are almost insoluble and the latter solu- 

 ble. The analytical results obtained by this method did not 

 decide the question.* However, it is probable that in the 



* 100 grm. silt and the same quantity of sediments -25 mm h. v.-8 mm h. v. were 

 treated each with 300 c.c. dilute acetic acid (25 parts glacial acetic acid to 75 

 parts water) for five days at ordinary temperature. 



I. The silt yielded . -0074 grm. P 2 O s . 



II. The sediments -25 mm h. v.-8 mm h. v. yielded... -0043 grm. P 2 5 . 



