178 ON TARES, AND ON CLOVEK. 



diminishing the weight of the grain per bushel. The common 

 salt in this case was applied in a dose which was large for a 

 top-dressing, and so late as the 13th of May, but rain fell 

 immediately after, and this probably prevented it from injuring 

 the young corn, and made the result a favourable one. 

 4. On tares by Mr Finnic, Mid-Lothian, in 1843 



Nothing gave . . 846 stones, cut green 

 Nitrate of soda, 123 Ib. . 935 ... 



Increase,. . 89 stones. 



The relative quantities of dried produce were not ascertained. 



5. On grass and clover, to be cut for hay, numerous experi- 

 ments have been made and published. I insert only four sets 

 of results in which the effects of different nitrates are compared. 



a Mr Gardner, at Barochan, Renfrewshire, in 1844 top- 

 dressed sown grasses on the 7th of May, and obtained from the 

 several portions the following weights of hay per imperial acre 



Nothing yielded . . . 26^ cwt. 

 Nitrate of soda, 1| cwt. . . 37 

 Nitrate of potash, 1 cwt. . . 40| ... 



Both nitrates added largely to the crop ; and supposing that 

 duplicate experiments would have made no difference in the 

 above numbers, the nitrate of potash acted more favourably upon 

 the soil than that of soda, since, according to the equivalent 

 numbers, one-fifth more saltpetre ought to have been added to 

 produce an equal chemical effect. 



b Two other experiments made at the same place in a sub- 

 sequent year, on two different fields of loamy soil, gave the 

 following weights of hay per imperial acre : 



1. 2. 



Nothing, . . . 22 cwt. 27^ cwt. 



Nitrate of soda, 2 cwt. . 51 ... 56 



Nitrate of potash, 2 cwt. . 57 ... 48^ ... 



These two results, as they stand, lead to opposite conclusions 

 in regard to the comparative merits of the two nitrates. The 

 addition of one-fifth to the quantity of the nitrate of potash 

 employed might, however, have raised the produce from the 



