324 



EXPEEIMENTS ON TURNIPS. 



These superphosphates were guaranteed to contain a minimum 

 of 25 per cent. " soluble phosphates," and to be in a sufficiently 

 dry and joowdery condition for sowing. The " reduced" phosphate 

 is included under the heading of Tricalcic Phosphate made 

 Soluble, in the preceding Tables (II., V. &c.), as the phosphoric 

 acid soluble in water soon assumes this form after application to 

 the soil In buying superphosphate, however, the " reduced " 

 phosphates should not be included along with the soluble in the 

 guarantee, for putting the same value on " reduced " as " soluble " 

 phosphates induces the manufacturer to use a mineral containing 

 much iron. It also introduces an element of uncertainty in the 

 guarantee, for " reduced phosphates " are seldom determined, and 

 if chemists are specially requested to do so, the various methods 

 pursued are not sufficiently constant in their results. Moreover, 

 reduced phosphates are inferior to soluble, inasmuch as they 

 have lost at least their diffusive power. 



Analysis of Nitrate of Soda. 



Tlie nitrate of soda was equally good both seasons, and con- 

 tained 97 per cent, of the pure salt, 100 parts of that used in 

 1883 contained nitrate of soda 97*05, moistures 1*74, insoluble 

 — •03, chloride of sodium="91, and sulphate of soda="27. 



Prices noted include carriage to Killearn Station. The 

 manures were bought in the end of February each season, and 

 the prices represent their value at that time, except the nitrate 

 of soda used in 1882, which was ordered on 8th April. With 

 the exception of the ground mineral used in 1883, the quotations 

 were for considerable quantities, and for cash within a week after 

 delivery. Had much ground minerals been used in 1883, it 

 might have been bought for 7s. 6d. per ton less. 



