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V. — On the Comparative Value of different Artijicial 
Manures for raising a crop of Siocdes, roith Rcmarhs on the 
Composition of the Manures employed in Jixperirtiental Trials 
made at the Royal Agricultural College, Cirencester. By Dr. 
Augustus Voelcker, Professor of Cliemistrj in the Royal 
Agricultural College, Cirencester. 
It is strange, that whilst an extended experience has proved in 
the most positive manner the specific action of phosphatic 
manures, and the decided advantages which result from their 
application to root crops, the employment of manures either 
greatly deficient in phosphoric acid, or wanting altogether this 
important fertilizing agent, should still be recommended by some 
practical men for raising a crop of swedes, turnips, or any other 
root crop. No less strange appears the preference which some 
farmers give even to half-inch bones over superphosphate of lime, 
although the superior value of the latter fertiliser has been 
ascertained in numerous practical experiments, and consequently 
has been recommended by high agricultural authorities, as by 
far the most economical form in which bones ought to be applied 
to the land. Still more surprising appears the ready sale which 
many artificial manures find, although their composition plainly 
indicates the utter worthlessness of the manufactured article, or 
the great discrepancy between the price at which it is offered for 
sale, and its per centage of really valuable fertilising constituents. 
But strangest of all, it strikes us, is the fact that the sale of down- 
right trashy manures, or to say the least of them manures of a 
very inferior description, is often perpetuated for a long time by 
high flourished testimonials, given by men of character, and 
possessed of a degree of practical skill which entitles them to 
a considerate hearing. It is further worthy of observation, that 
valuable artificial manures are often employed even by good 
farmers in the cultivation of crops on which, as experience has 
proved, they are used with far less advantage than on others. 
Thus for instance, in many parts of England, but more especially 
in Scotland, Peruvian guano is used extensively as a manure 
for turnips, in preference to superphosphate of lime, not- 
withstanding the publication of numerous comparative field 
experiments, which have established the superior value of super- 
phosphate as a manure for root crops, and wliich have shown 
likewise that the greatest fertilising effect of guano is realised 
by applying it to a white crop or to grass land. 
Strange as these facts may appear at first sight, yet a little 
consideration, I think, will point out the reasons on which the 
objectionable practices to which reference has just been made are 
founded. Is there not afforded a clear proof in these and similar 
