132 EXPERIMENTS WITH SULPHATE 



soil from one to ten or twelve hundredweight an acre, for 

 example ; and 



Second on different crops, applied also in increasing doses. 



The facts above stated will thus be tested, and also whether, 

 if true of one, they are also true of other crops. 



4. Results of experiments with sulphate of magnesia applied 



alone. 



Of published experiments made with sulphate of magnesia 

 applied alone, the following are nearly all which have come to 

 my knowledge : 



1. On oats, a By Mr Main, at Whitehill, Mid-Lothian. 



Per bush. 



Nothing gave . . 42 bush., weighing 40 Ib. 



Sulphate of magnesia, 2 cwt., 56 ... ... 37| lb. 



b By Mr Fleming of Barochan, Renfrewshire, on land 

 trenched with the spade out of a nine years' old lea. 



Grain. Straw. 



Nothing, (mean of 4 plots,) . 51 bush., weighing 30 cwt. 

 Sulphate of magnesia, 2 cwt., . 47 ... ... 28 J ... 



Sulphate of soda, 2 cwt., . 45 ... ... 29| ...* 



The experiment of Mr Main is favourable ; but we cannot 

 rely upon either of them, from the want of duplicate experiments. 

 At Barochan, the land ought to have been sufficiently rich natu- 

 rally ; but we are unable to judge of the exact effects, because 

 we have neither duplicate results of the effects of the two sul- 

 phates, nor the exact produce of each of the four plots to which 

 nothing was applied. Some of these four might yield less than 

 either of the dressed plots ; and if so, the apparent lessening 

 effect of these saline applications would disappear. 



2. On clover and rye-grass, cut for hay by Mr M'Lean, 

 Braidwood, Mid-Lothian, in 1842. 



Nothing, 125 stones per acre. 



Sulphate of magnesia, 1^ cwt., . . 290 ... 

 Gypsum, 3 cwt., ... 200 ... ...f 



The value of these results is somewhat diminished by their 



* Transactions of the Highland Society, March 1845, p. 421. 

 f Ibid. July 1843, p. 34. 



