EXPERIMENTS ON GYPSUM. 



131 



Three equal weights of the same manure, fresh as it is taken 

 out of the fold-yard, and as equably mixed as possible, should 

 be placed for two or three months in the same circumstances. 

 One of the three portions should be immediately mixed with 

 a weighed quantity say two or three hundredweight of 

 gypsum to 20 tons of manure and at the end of the three 

 months, all the three portions should be used on the same soil 

 for the same crop treated in every way the same. Three 

 duplicate experiments must be made: two with the manure 

 with which the gypsum has been mixed, two with the manure 

 in its natural state, and two more with this manure, plus a 

 quantity of gypsum applied to the soil after or along with it, 

 and equal to that which the gypsumed manure contains. This 

 latter addition is for the purpose of testing and eliminating the 

 effect which the mere addition of gypsum, irrespective of any 

 chemical action, would have upon the manure, the soil, or the 

 crop. The following scheme shows the arrangement : 



I think such experiments as these would set at rest the value 

 of the theoretical view I have above stated, as well as the ques- 

 tion as to the economical value of gypsum used in this way, to 

 the practical farmer. 



i There is still another point to which attention should be 

 drawn. One or two hundredweight of gypsum are said to 

 produce as good an effect as a larger dose, but that larger 

 doses do no harm. Are these statements correct ? * Are they 

 so in regard to all soils, crops, seasons, and climates ? Accurate 

 experiments should be made as to the effects of gypsum when 

 applied 



First in different doses to the same crop on the same 



