262 BULLETIN OF THE BUSSEY INSTITUTION. 
It will naturally be asked, how it happened that Boussingault, in his 
experiments, already alluded to on page 252, arrived at conclusions so 
unlike those to be drawn from the results of Wolff and myself. I 
think the chief reason why the plants in Boussingault’s trials derived 
so little support from the soil-nitrogen, will be found in the fact that 
the quantities of loam employed by him were both comparatively and 
absolutely very small. The following examples will give a general 
idea of the character of Boussingault’s mixtures. They are taken 
from the first volume of his “ Agronomie, &c.”:— 
The mixture consisted of |" Page 299. | Page 304. | Page 331. | Page 348. | Page 352. 
Gardén Loam .. . .| 1380grms.|} 130 grms.] 130 grms.| 100 grms. 50 grms. 
Sulicious Sand .- J . .| 1000'erms: |° 200 grms:|| 720 Gris) eee 125 grms. 
Fragments of Quartz. .| 500grms.| 300 grms.| 150 grms. TD cts hee eee 
Ashesof Hay . .'s'. 0.2 grm. 0.1 grm. 0.lgrm.*| 0.05 grm.*| 0.05 grm.* 
Phosphate of Lime’ vt. ta he) | aa 0.1 grm. 0.1 grm. 
Wolff, on the other hand, commonly took at least 200 grammes of 
earth, by itself, for each of his experiments, and apparently he some- 
times used more. The quantities of peat and loam employed in 
my own experiments, as reported above, ranged from 2380 to 500 
grammes; and I have found by other experiments that less favorable 
results are obtained when quantities much smaller than these are em- 
ployed, or when a very large proportion of sand or other inert material 
is mixed with the loam. The following table will illustrate the latter 
point. The experiments to which it refers were made in the spring 
The Jar contained d The Crop, harvested May 22, 1873, 
Loam from 
Bussey Plain- 
field, grms. 
Loam : : | 
Berkshire t rab gaged Grew to height | Had 
oO 
Sand, grms. | Sand. [3+ 90°to100°c.| inches. Seeds. 
11, 19, 25, 26 
. 20 to 24 
8, 20, 21, 26 
: 3 |Nothing grew 
se ed ae a 
sh fie 2/08. 
* Ash of dung. 
t Only one plant. There were four plants in each of the other jars, ex- 
cepting No. 4. 
