6 Artificial Manures for Swedes. 



farmer, that he has little inclination for undertaking experimental 

 trials in the field. 



Another circumstance to which reference has been made as 

 calculated to vitiate the results of field experiments, and to give 

 rise to erroneous views with regard to the value of fertilising 

 materials, is the improper state in which otherwise good manures 

 are occasionally applied to the land. An example or two, 

 which came under my personal observation, will I hope bear me 

 out in making this remark. I have repeatedly heard it asserted 

 by good farmers, who had tried both the ammoniacal liquor of 

 gas-works, and the refuse tar at the same manufactories, that 

 gas-tar produced a much better result on grass and wheat than 

 the ammoniacal liquor, and that consequently the former refuse 

 was worth more in an agricultural point of view. On further 

 inquiry I learned the reason of the small estimation in which 

 this liquid was held by those who preferred to employ the gas-tar 

 as a manure. The ammoniacal liquor, I was told, burns up the 

 grass, whilst gas-tar makes it look more green and succulent. 

 Here we have a striking example in illustration of the entertain- 

 ment of erroneous views, to which an improper application of 

 manures is apt to lead. Ammoniacal liquor of gas-works is far 

 too powerful a manure to admit of its application in an undiluted 

 form, and when used unmixed with water or any other diluting 

 substance, as was here the case, it invariably burns up vegetation 

 almost completely, unless a continued fall of rain provides for 

 the necessary dilution, which has been neglected by the farmer 



Ammoniacal liquor owes its chief fertilising value to the 

 ammonia, which exists in it almost altogether as a carbonate, 

 and contains nothing detrimental to vegetable life ; but like 

 oxygen, which is so essential for animal life, carbonate of 

 ammonia must be considerably diluted in order that it may 

 produce a beneficial effect. In gas-tar, on the other hand, but 

 little carbonate of ammonia is present ; and for this reason it 

 may be applied to the land undiluted, without fear of burning up 

 the young plants. But it does not follow from this that gas-tar 

 is a more valuable manure than the ammoniacal liquor, for it is 

 easy to prove that gas-tar is only in so far valuable as a manure, 

 as it is mixed with the watery ammoniacal liquor of gas-works. 

 Both these refuse matters are collected together in one tank, and 

 some of the watery ammoniacal liquor therefore remains always 

 mixed with the tar. In the tar itself there are present no sub- 

 stances which contain either nitrogen, phosphoric acid, or potash, 

 nor indeed any constituent which has the slightest fertilising 

 value ; for the organic, resinous, and oily compounds occurring 

 in gas-tar are all compounds of carbon and hydrogen, or carbon, 

 hydrogen, and oxygen, and as such they will furnish, on ultimate 



