F. FLETCHER. 9 
The crops were harvested, roots and all, every 21 days, and 
in all, three crops were taken from each dish between the 10th of 
January 1907 and May 15th. The water in the dishes was kept 
up to 4 litres by adding well water every few days. 
The crops grown were cotton, sorghum, cajanus indicus, 
sesamum, wheat, gram (Cicer arietinum). 
The air dry weights (including the roots) of the three har- 
vests of the several crops is given in Table V. 
TABLE V. 
Air dry weights of crops and the amount of water into which the excreta had passed. 
| cits 
| Volume of well oye Total volume 
Now N: f No. of plants | Air dry weight | in which their ex- | of water 
ileal pases se enone grown. in grammes, creta was finally evaporated 
contained. and replaced, 
| 
Litres. Litres. 
1 | Cotton ... Get 246 9170 2°3 19°00 
2 Sorghum 22 | pees 6°026 23 18°25 
3 | Cajanus .. =e 157 6407 23 19°25 
4 | Sesamum ie: 133 0°746 12 18°75 
5 Wheat es | 261 7-766 12 19°75 
6 | Gram | 201 19-308 12 27°75 
The volume of water remaining in the dishes on harvesting 
the third crop was allowed to stand in a room until its volume 
was reduced to the quantity stated, this quantity having been 
indicated in previous tests to be the best for the final test. 
Water culture in the excretory solution. 
For brevity the various solutions obtained will be called 
‘cotton water,’ ‘sorghum water, ’ etc. 
The water cultures were made in wide-mouthed bottles 
holding 100 c. c. when filled up to the neck. The mouth was 
plugged with a teakwood stopper in which four holes (4 inch 
diameter) were bored. Through these holes the radicle or the 
plumule of seedlings germinated in crushed quartz was passed, 
the seedlings being supported in place by a small wad of 
cotton. 
In the case of cotton, cajanus and sesamum, the root was 
passed downwards through the stopper; in the other cases the 
