AGGREGATE RESULTS. 13 
then have been reduced to less than 1 per cent. This would 
apparently not occur, as on Area 4 there was still a P.c. fr. of 1-8 
at 134 years. 
The large decrease on Area 1 from 19-7 per cent. at 44 years 
to 13:2 per cent. at 54 years, strongly suggests that the decrease 
on these areas was at first rapid, but became slower lateron. The 
results for Areas 1 and 3 do not agree with those for Area 2 at 
corresponding periods however, although there was relatively little 
difference between Areas 2 and 3 at g$ years. These differences 
may be due either to the different treatment given to the areas, or 
to the composition of the seeds-mixtures used. 
The results for Area 6 are in marked contrast with those for 
the other areas, even with those for Area 7, which was in most 
respects comparable with it. A P.c. fr. of 73-3 at 44 years is 
exceptionally high, as also are the other results in succeeding years 
on the same area.* 
Areas 6 and 7 had similar soil conditions, and their treatment 
was mainly similar throughout. The only difference in treatment 
was, that Area 6 was mown for hay at 1} years while Area 7 was 
grazed. It may be that this placed Area 7 at a disadvantage— 
that by being grazed in the first season a large proportion of the 
sown grasses was uprooted. This is probably not the case, as in 
this, and even in the following year, it was grazed with cattle only. 
The difference in altitude would be expected to give the 
advantage to Area 7,? so that apparently the chief cause of the 
difference was the difference in the composition of the seeds- 
mixtures. 
(4) Not sown. 
Areas 2 and 4 appear to agree fairly closely, but again there 
was a considerable difference between Areas 2 and 3 and between 
Areas 1 and 2. These differences are probably partially explained 
when the individual species are considered,3 but they may also 
have some significance in connection with the treatment of the 
* Cf. (18). 
2 This would perhaps depend however on the nature of the seeds sown, 
8 See Anthoxanthum odoratum, p. 27, especially, 
