56 BULLETIN OF THE BUSSEY INSTITUTION. ‘ 
to potash and phosphoric acid than ordinary sand. In the hope of 
throwing some light upon this point, a series of experiments (C, 
planted December 9, 1872) was undertaken, precisely similar to those 
in Series B, with the exception that the 525 grammes of ashes were re- 
placed by 1,000 grammes of pit-sand taken from an excavation in the 
field next adjoining the Plain-field of the Bussey Institution. _ This 
pit-sand constituted a bed or layer two or three feet thick in the coarse 
drift, granitic (1) gravel of the locality, and was situated about three 
feet below the surface of the ground. The sarid was dug out by it- 
self, apart from the gravel, to be sold for-making mortar. It was a’ 
clean, gritty, yellow sand, composed mainly of quartz, and seemed at 
the first glance to be sufficiently ill-adapted for the support of grow- 
ing plants, though on closer inspection fragments of several kinds of 
rocks could be seen everywhere interspersed among the silicious par- 
ticles. The sand was placed in the jars in the condition in which it 
was obtained at the pit. It was not washed or purified in any way. * 
The results of these experiments are set forth in the following 
table : — 
The crop (harvested March 4, 1878). 
No. 0: The wigs ra Weighed in 
jar. watered wit grammes Gq to heicht Had 
Co his et bas: Be Remarks. 
degrees C.). 
1 Nitrate of potash . 1.410 15 27 
2 ; Se aR a 0.360 18 | 7.) Onkaeogaeeee 
3 | Nitrate of lime 1.600 14 
Nitrate of potash and 
4 sulphate of magne- 1.485 14 
sia . aR 
5 Rain-water. . 0.065 best = 
6 | Nitrate of ammonia 1.075 15 
7 | Phosphate of potash 0.325 13 
Nitrate of lime and 
8 phosphate of eke 1.715 best = 20 
ash? , 
Sulphate of magne- 
9 sia and phosphate 0.145 9 
of potash . ; 
Nitrate of lime, sul- 
phate of magnesia, 
10 and phosphate of 1.960 ht 
potash. . 
( Nitrate of lime, e) 
11 phate of magnesia, f 1.760 17 
Wega man of ibe 
ye sag 
J trate of potash, sul 
