MANURES AXD TliEIR APPLICATION. 315 



special virtue in dissolved bones, but that the same, or even 

 better results, can be obtained by the use of superphosphate and 

 sulphate of ammonia mixed in proportions to imitate the com- 

 position of dissolved bones. 



Considering the enormous quantity of mineral phosphates 

 which are now available for the manufacture of superphosphate, 

 I am strongly of opinion that it is a mistake to dissolve bones," 

 and that they are put to a much better use by applying them in 

 their natural state in as finely ground a condition as they can 

 possibly be got. The germ life in the soil, and in the bone, will 

 very rapidly convert the whole into a form available for the 

 nourishment of plants, but to dissolve bones in sulphuric acid is 

 to kill out the germ life within it, and retard the delay of any 

 nucleus of bone it may contain. The fashion of vitriolating 

 bones is in my opinion open to the same, or to still greater 

 objection, for not only is the germ life in the bone destroyed, but 

 after the superficial layer of dissolved bone is removed, there 

 remains a kernel of bone which will remain undecomposed in 

 the soil for a very long time. 



Regarding mineral phosphates, considerable discussion has 

 taken place of late as to whether it is better to dissolve them 

 into superphosphate, or to use them in their natural state, but 

 ground down to an impalpable powder. It is an interesting 

 question, and one that may easily be discussed impartially and 

 without acrimony. 



From all that I have been able to learn either by experience 

 or by reading, I am forced to the conclusion that when equal 

 quantities of phosphate of lime are used in the dissolved and in 

 the undissolved state, the advantage is clearly in favour of the 

 former in four directions — firstly, in the certainty of its action ; 

 secondly, in the rapidity of its action ; thirdly, in the amount of 

 crop it is able to produce ; and fourthly, in the earliness of the 

 maturing of the crop. These are four weighty considerations, 

 and in this uncertain climate the last is perhaps the weightiest 

 of all. But there are other circumstances to be taken into 

 account; there is a certain amount of expense involved iu the 

 dissolving of a phosphate — there is the work of dissolving it and 

 the cost of the sulphuric acid employed ; and shilling for shilling 

 it may be found that to use the undissolved phosphate is the 

 cheaper in the end. Moreover, I have seen experiments con- 

 ducted with great care in Forfarshire, where the crops produced 

 were markedly in favour of the undissolved phosphate, apart 

 altogether from the cost; and I am forced to the conclusion that 

 this is not a question to l)c decided ex cathedra, or by any one 

 man operating on any one soil, but that each district must 

 determine for itself what is the most appropriate and economical 

 form of phosphate to employ. In a country like ours, with such 



