Experimental Crops at Rothamsted. 
95 
(luring; the months of April, May, and June, which may be 
tonsidered as including the period of active growth of the hay- 
crop. 
Although there is much to be learnt from the results brought 
together in the foregoing Table, much more information than 
is there given would be required — as to the difference in the 
character of the herbage produced under the different conditions, 
the distribution of the rain, the degree and range of tempera- 
ture, and the mutual adaptations of moisture, heat, and stage of 
growth) of the plants — to enable us to account for all the fluc- 
tuations in the amounts of gross produce which the records 
show. 
It is seen at a glance that the fluctuations from year to year in 
the amounts of produce without manure, though doubtless greatly 
dependent on the quantity and distribution of the rain falling 
during the period of active growth, by no means correspond with 
the fluctuations in the total amount of rain during the three 
months. Thus, the average fall for the three months is 6"56 inches, 
and the average produce of hay without manure is 22| cwts. 
But we have, with almost exactly the same total amount of rain 
during the same period in 1863 (6*57 inches), only 20|- cwts. of 
hay ; whereas, with even rather less (6'43 inches), in 1869, we 
have the heaviest produce obtained in any one of the series of 
15 years, namely, 38 cwts. The fact is that, coincidently with 
the small produce of 1863, less than one-third of the total rainfall 
of the three months occurred during the first two months of the 
period ; whilst, coincidently with the very heavy produce in 
1869, there was considerably more than the average fall of rain 
in both April and May, and less than half the average fall in 
June ; the result being that more than five-sixths of the total fell 
during the first two of the three months, when its influence upon 
the growth would be the greatest. Again, the heaviest total fall 
within the growing period was in 1860, when there was nearly 
double the average amount, whilst the produce only exceeded the 
average by less than 2 cwts. of hay ; the facts being, that about 
half the total amount fell in J une, that is, not until the last month 
of growth ; and that the temperature was very unusually low 
almost throughout the period of active vegetation. 
The lowest amounts of produce were — IT^^ cwts. in 1868, 11|- 
cwts. in 1865, and only 5f cwts. in 1870. This last, the lowest 
amount in the series, is coincident with the smallest amount of total 
rain over the three months throughout the fifteen years, namely 2-79 
inches. With only 3*29 inches in the three months of 1868, there 
was a produce of 17^ cwts., but with 4 2 inches in 1865, there 
was only llj cwts. But whilst, in the latter year, there was 
in April only about one-fourth the average fall, and very high 
