Artificial Manures Jo?- Swedes. 
93 
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 tlie 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 1 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 fui'nish, on ultimate 
