21i 
The Present State of Agriculture 
Tons. Cwt. 
1st portion , . . 119 
2iid portion . . . 8 14 
Difference . . 2 15 
— a (lifTercnce of nearly 3 tons on a crop of from 9 to 12 tons. 
How much of this was owing to those natural difTereiices in the 
soil which in unmanured portions gave rise to the difference in 
the crop of 1| ton per acre, which I have already quoted; and 
how much to some unexplained diversity in the acticm of the 
manure employed? Had anything in .addition to the bones been 
applied to the first of these dressed portions, we should natu- 
rally have ascribed the increase of 2| tons to the special action of 
that substance. And yet how wrong would this have been, not 
only theoretically, but how much practical evil might it have 
caused ! how much throwing away of money in the purchase of 
this substance by practical men in after years! 
But I present you with a more striking illustration from expe- 
riments made in the island of Bute in 1817, and recently pub- 
lished. On the farm of Kerrytoniia, on a dry soil resting on the 
old red sandstone, three portions of the same field, manured 
alike with 24 carts of farm-yard dung and IG bushels of bones, 
gave respectively 34|, 32^, and 271 tons of swedes. The dif- 
ferences were — 
Between the 1st and 2nd portions, 2i tons. 
Between the 2iid and 3rd portions, 7i tons. 
On another farm, in the same island, that of South St. Colmac, 
the soil being a deep loam, three portions on the same field 
dressed with 5 cwt. of African guano each gave respectively of 
Dale's hybrid turnips (bulbs) per Scots acre — 
Tons. Cwt. 
1st portion ... 28 5 
2nd portion . . . 29 17 
3id portion . . . 31 17 
Difference between 1st and 3rd 3 12 
What confidence can be placed, what numerical deductions can 
we venture to draw, from results differing so widely as these ? 
And then among experiments tabulated in a formidable 
manner, and with all the strength of numbers, we sometimes find 
it stated that less .of a substance gave more, and that more of it 
gave a less produce. Thus on the field last quoted in Bute — 
Tons. Cwt. 
/) cwt. of guano in one experiment gave 31 17 
4 „ „ 32 0 
6 „ „ „ 30 15 
