174 



Analyses of Ashes of Plants. 



solid matter it contains ; 10 per cent, (or 2 cwt. in every ton) 

 the average amount of solid matter in the turnip bulb, but in 

 the table an instance is seen where the solid matter is as low as 

 7'3, another in which it reaches 14-0 — in other words, 10 tons of 

 Specimen 81 contain very nearly as much solid nutritive matter as 

 20 tons of Spec. 94. 



It is not easy to over-estimate the importance of this circum- 

 stance. If the table is examined it will be seen that the specimen 

 alluded to (No. 81) as exhibiting the largest amount of solid matter 

 in a given weight of bulb, has also (with two exceptions only) the 

 least water in the top — in other words, as a whole this particular 

 crop is weight for weight much more valuable than any other 

 in the table. But if its history be asked for, it will be found 

 that it was grown without manure, and was consequently not 

 expected to be a good crop. For the sake of illustration let us 

 compare this specimen with No. 79, grown on the same field, but 

 in which, from the use of superphosphate of lime and guano, there 

 is an increase of 3 tons 5 cwt. on the acre : — 



Table 2. 





Spec. 



Water per Cent. 



Produce. 



Dry Weight in lbs. 







Bulb. 



Top. 



Bulb. 



Top. 



Bulb. 



Top. 



Total. 







79 

 81 



88-0 

 86-0 



84-0 

 82-0 



tons. cwt. 

 12 0 

 8 5 



cwt. 

 15i 

 15' 



lbs. 

 3230 

 2743 



lbs. 



263 



303 



lbs. 

 3493 

 3046 





It will be seen by this table that there is an increase in the dry 

 weight by the use of artificial manure, but by no means to the 

 same extent as in the wet produce : — 



The apparent increase (that on the wet weight) is 35 per cent. 

 The real increase (that on the dry weight) is 14 per cent. 



It were easy to draw comparisons between many of the crops 

 in the table, which would show that the gross weight of the crop 

 may but ill represent its value as compared with any other crop 

 of greater or less produce. It is obvious then, however destruc- 

 tive it may be of the confidence to be placed in the experiments 

 on record or the growth of turnips, that one vital circumstance 

 has been usually omitted — the dry loeight of the crop. A par- 

 ticular manure may raise 3 or 4 tons more turnips on an acre, but 

 the greater crop may be even les§ valuable than the smaller pro- 

 duce, the excess of weight being more than counterbalanced by 

 the greater proportion of water. 



The same remarks will apply to the relative value of different 

 crops in feeding sheep or cattle. 



But this truth, unpalatable as it must be, should not discourage 



