AQUEOUS SOLUTION OF TH-E SOU,, 321 



solution was diminished either by reducing the proportion 

 of soHd matters below 0.5, or increasing it to 2 parts in 

 1,000 of water. The proper dilution of the food of plants 

 for most vigorous growth and most perfect development 

 is thus approximately indicated. 



We notice, however, considerable latitude as regards 

 the 2^roportions of some of the most important ingredients 

 Vhich are usually present in least quantity in the aqueous 

 solution of the soil. Thus, phosphoric acid in one case is 

 thrice as abundant as in the other. We infer, therefore, 

 that the minimum limit of the individual ingredients is 

 not fixed by the above experiments, especially not for or- 

 dinary growth. 



Birner and Lucanus communicate other results ( Vs. St., 

 VIII., J). 154), which throw much light on the question un- 

 der discussion. They compared the growth of the oat plant, 

 when nourished respectively by a rich garden soil, by 

 ordinary cultivated land, by a solution the composition 

 of Avhich is given above, and lastly by a natural aqueous 

 solution of soil, viz., a well-water. Below is a statement 

 of the weight in grams of an average plant, produced iia 

 these various media, as well as that of the grain yielded 

 by it. 



Dry crops compared 



Weight of aver- Weiirht of with seed, the hitter 



age plant, dry. dry Grain. taken as unity. 



Garden 5.27 1.23 193 



Field 1.75 0.63 &i 



Solution 3.75 1.53 137 



Well-water 2.91 1.25 lOG 



We gather from the above figures that well-water, in 

 quantities of one quart for each plant, renewed weekly, 

 gave a considerably heavier plant, straw, and grain, than 

 a field under ordinary culture ; the yield in grain being 

 dovble that of the latter, and equal to that obtained in a 

 rich garden soil. 

 14* 



