DISCORDANT RESULTS. 49 



eighths of an acre of the same experimental field, Mr Fleming 

 obtained, of early Liverpool yellow turnips, at the rate of 



First portion, . . 12 tons 17 cwt. per imperial acre. 

 Second portion, . . 11 ... 8 ... 



Difference, ... 1 ton 9 cwt., or about ^th, or 12^ 



per cent of the whole crop.* 



3. Mr Chalmers of Monkshill, in Aberdeenshire, from two 

 un-manured eighths of an acre of grass-land, obtained of hay 

 respectively 



First portion, . . 385 stones. 

 Second portion, . . 281 



Difference, . . . 104 stones, equal to two-fifths of 



the smaller crop, very nearly. 



4. So at Erskine, in Renfrewshire, an experimental grass 

 field, cut for hay, yielded, from each of two quarters of an acre 

 respectively 



First portion, . . 838 Ib. of hay. 

 Second portion, . . 726 



Difference, . . . 112 Ib., or l-7th of the whole: 



From these results it appears that, upon land in an ordi- 

 nary condition, two portions of the same field supposed to- 

 be equal in quality, and for that reason selected as especially 

 fitted for experimental trials may naturally yield very con- 

 siderable differences of crop, even when no manure is added to 

 them. 



It should also be borne in mind, that a single difference be- 

 tween two experiments made on the same field, cannot be safely 

 regarded as an index of the maximum differences which the 

 several parts of the field would be found to yield. When we 

 make two experiments on a field, we find a certain difference 

 between the two results. But if we had made a third, a still 

 larger difference, compared with one of the other two experi- 



* Appendix to my Lectures on Agricultural Chemistry and Geology, 1st edit., 

 p. 56. 



D 



