EXPERIMENTAL STUDY. 39 
different plants in the various media were continued up to June, 1901. 
Not only does it take some time to get assured results in culture experi- 
ments, but owing to the various elements involved in many soils 
employed it is necessary to have accumulative evidence to warrant 
safe deductions. In making the experiments, water, sand, and soil 
cultures were employed and comparisons made of many trials in the 
different media used. In the sand and soil cultures the calcium and 
magnesium were incorporated as carbonates, sulphates, and nitrates. 
In water cultures the more soluble salts of nitrates and sulphates were 
employed. In comparing the two bases the molecular weights have 
been used for reasons readily apparent. If there is a ratio of effect 
between the two elements the molecular weight is the better basis of 
estimating it, but in agricultural practice the actual weight, as a matter 
of course, would be found the more practicable. However, as may 
be readily seen, one ratio may be quickly estimated from the other. 
LIME AND MAGNESIA AS NITRATES AND SULPHATES IN WATER 
CULTURES. 
The following series of water cultures were made in bottles holding 
250 c.c., the stem of the plant being supported by a cotton plug in the 
mouth of the bottle. The bottles were placed in a box covered with 
sand to exclude light from the roots. The plant used was a variety of 
cowpea which had been sprouted in clean sawdust. 
These experiments were preliminary and made not alone for the evi- 
dence shown by the results attained, but as a basis to guide in more 
extended trials. It was not attempted to bring the plants to maturity 
in the small amounts of culture media used, but to carry them beyond 
the point where a direct physiological result would appear from the 
addition of the various percentages of the lime and magnesia salts 
employed. 
The following solutions of magnesium and calcium salts were made 
up with distilled water, and plants 5 cm. high were set July 17. The 
results are shown in the following table: 
tesults of experiments with cowpeas set July 17. 
July 17. July 20. July 23. 
No. of == 
bottle. Solution. Per cent. | Condition. | Condition. | 
iby WIN EOS a ha Oe oo al Se ae ea Eesilitihy 4-255 eee | Drooping. 
S VEO as MSAOs: 520-52. -3-.=-.- Ox?) || ejected! 58 ee ee ee | Dead. 
3 | MgO as Mg(NOsz)o--..-.-------- 0.1 | Leaves shriveled ......... Dying. 
i) Cee an GniNO.)e- 2.2 2. _ 2.2. 0.1 | Hregithy 202 | ee See |Healthy. | 
' | MgO as Mg(NO,)o .....------- 0.05 
5. | FE Healiny oie. te eee Healthy. | 
5) CaO as Ca(NO;)o.....-.-.----- Th ope eey 
MgO as Mg(NOg)o ..---------- 0.05} 
6 : A Heal thige 4 4 eee Healthy. 
CaO as Ca(NOg)o.-.----------- Nei | eeacane: oe 
| MgO-as MgSO,.........-...-.. 0.1 |) 
7 Heshkiiiy. es eee oes. Dead. 
i OS a ee Ss Oey lag ase Sauces 
