BULLETIN OF THE BUSSEY INSTITUTION. 265 
times as much as the seed, while another pot that contained the same 
amount of nitrogen (0.1 gramme) in the form of a nitrate, gave a crop 
that weighed fourteen times as much as the seed, although, as has just 
been shown, the crop from the garden soil was two or three times as 
good as that from a soil totally devoid of nitrogen; or that he was 
surprised to find in his experiments with lupins that 0.34 gramme 
of the soil-nitrogen, that is to say, as much of that element as is con- 
tained in 2 or 38 grammes of saltpetre, gave crops that were but little 
if any better than those got from sands devoid of nitrogen, but charged 
with the ash ingredients of plant food. 
The experiments made by Boussingault really proved, not that the 
soil-nitrogen is of little worth, but that, as is indicated by a mass of 
other evidence, it is generally speaking far less valuable than the 
nitrogen contained in manures. In other words, he found that very 
much more nitrogen, taken as it exists in loam, is required to. pro- 
duce a given effect, than when taken in the form of a nitrate or of an 
ammonium salt. 
_ The following experiments by Professor Johnson,* of New Haven, 
afford an excellent example of the use that can be made of the soil- 
nitrogen by plants that are well supplied with the ash ingredients of 
The Crop 
it } 270 grms. Peat, pets 10 grms. of the 
ashes, and 3 grms. Peruvian Guano 
No. of P The Crop weighed, | weighed more 
the Pot. The Pot contained air dried, grms. than the Seed, 
imes 
j 
: } miparme. or Peat. . . . 1 + 2 { ee HOG atten: Se 
8 } 270 grms. Peat, plus 10 grms. of ashes 
4 { 14,19 
of young grass . cee ei rahl gee 
5 i 270 grms. Peat, plus 10 grms. of the 
6 ashes, and 10 grms. Carbonate of 
| iis. opt ae See A peg 
20.2! 
7 } .270 grms. Peat, bd 1 10 grms. of the 
S ashes, and 10 grms. of ries of 
| Lime. Et. builn Ee 
9 hi 270 grms Peat, shel 10 grms. of the : 
10 ashes, and 5 grms. of Lime slaked 
with a strong solution of common me aainh 
Salt Need 
* Copied from his work entitled ‘‘ Peat and its Uses,” New York, 1866, 
p. 79. 
VOL. I. 34 
