150 EXPERIMENTS WITH COMMON SALT. 



2. Comparative experiments with the chlorides of potassium, 

 sodium, (common salt,) and calcium, and with muriatic acid and 

 the carbonate of soda. 



The object of this series of experiments is to ascertain, in 

 virtue of which of its ingredients, or whether in virtue of both, 

 common salt has a given effect in given circumstances upon this 

 or that crop. If the chlorine alone be influential, the muriatic 

 acid applied alone should produce nearly a similar effect, (see 

 the following section.) If the salt act only by yielding soda, 

 the carbonate of soda should more easily and immediately pro- 

 duce similar effects ; and if it act as a compound body, a chloride, 

 then possibly the chlorides of potassium and calcium may exer- 

 cise a like influence. 



3. The comparative effects of muriatic acid, carbonate of 

 soda, and common salt, applied in equivalent proportions, to 

 different classes of plants. I mention this as .a separate series 

 of experiments, because, with three substances only, they can 

 be more easily made upon a number of different crops or different 

 plants. The inquiry, as the reader will see, possesses much phy- 

 siological interest in addition to that which attaches to the 

 practical applications of which its results may be susceptible. 



4. Experiments on the alleged effect of salt in strengthening 

 the straw of wheat and oats. Is it really so strengthened, made 

 stiffer, more shining, and more wiry ? Does this strengthening 

 arise from the straw being restrained in its growth, and being, 

 therefore, shorter and less in quantity ? Or is the stem thicker 

 and, therefore, stronger, or is its substance less cellular or spongy 

 and more compact ? In any of these ways the straw may be 

 made stronger, as well as by the absorption and fixing in its 

 substance of more silicious matter. The careful and minute 

 observer may do much good by determining 



a Whether the strengthening really takes place. 



b In what circumstances, or if in all ? 



c In what the strengthening consists. 



5. Does salt always add to the weight of the grain per bushel? 

 This is stated to be the case very frequently, and especially in 

 the case of oats. Thus, at Barochan, in Eenfrewshire, the 

 weight, per bushel, of salted and unsalted oats, barley, and 



