344 TlMEHRI. 
indeed, it would not be a difficult matter to select only 
the best joints of the best canes for that purpose.* 
At the same time the influence of manures in increas- 
ing the yield of cane is also clearly apparent from Mr. 
GlLZEAN's experiments. Thus $60 worth of the above 
manure produced 30.6 tons of cane per acre, $16 worth 
produced 19.8 tons, whilst the unmanured land only 
furnished in one trial 15.2 tons, and in the other 14.4 tons ! 
Apart, however, from increasing the yield of sugar or 
cane, a necessary function of manure is to supply the 
drain on the soil caused by the crop, and if manure 
is altogether withheld, exhaustion of the soil will 
ensue sooner or later, and the crops will languish 
and fail. Still this alternative may be of little 
moment, where abundance of new land is at dis- 
posal, although the question then arises, whether it 
is not more economical to keep up the fertility of 
the old soil, rather than prepare new as the other 
ceases to yield ? Considering that sugar cane is one 
of the least exhausting crops, and that the value 
of the minerals removed by it is small, the former 
course seems preferable, and appears to be gene- 
rally adopted in the colony. This being so, the 
point to be aimed at is to reduce the expense of manur- 
ing to a minimum compatible with efficiency, and, as 
already intimated, it is far from being even probable 
that the mark has been struck at present. 
With respect to the supply of nitrogen to plants, 
numerous experiments have been made in Europe during 
the past few years, with the object of comparing the 
* On purely theoretical grounds the writer anticipates that increased 
saccharine richness might follow the use of potassium salts as manure, 
