74 On the Inorganic Constituents of Plants, 



would weigh 58£ lbs. The same observations made to Gypsum 

 alone 15 may be applied to this square, the plants in it were 

 rather finer than in No. 16. 



17. Sulphate of Ammonia. This salt was applied at the rate of 

 3 cwt. per acre. Sulphate of Ammonia is now made on a large 

 scale from the refuse ammoniacal liquor of the gas works, either by 

 the addition of Sulphuric Acid, or by a cheap sulphate, such as 

 the Sulphate of Iron. The price of Sulphate of Ammonia is about 

 16*. per cwt. ; the abovementioned quantity therefore would cost 

 £2. 8$. per acre. The produce was 



The proportion of grain to the whole crop therefore was 

 as 2061 to 10000. One thousand seeds weighed 651 grains. 

 The standard measure full weighed 4166 grains, hence the bushel 

 would weigh 59^ lbs. The plants in this and the following square 

 18 began to show a marked difference in about three weeks 

 after the application of the salt ; the plants grew very vigorously, 

 and had the same deep green which distinguished those manured 

 with Muriate of Ammonia, 7 and 8. If there was any visible 

 difference between the effects produced by the Muriate and Sul- 

 phate, it was in favour of the former ; the plants manured with 

 that salt were perhaps a little more luxuriant than those treated 

 with the Sulphate. The plants in this and the following square 

 were rather less laid than those manured with the Muriate 

 7 and 8. 



18. Sulphate of Ammonia and Silicate of Potash. These 

 substances were applied at the rate of 3 cwt. of the former and 

 H cwt. of the latter per acre. The produce was 



