1879-] T/w Anomalous Season. 461 
was dry and warm. In the succeeding winter the only frost 
experienced was in February, and was of no long duration. 
The summer of 1858 was even finer than its predecessor, 
and was followed by winter free from frost and snow, save 
from about November 12th to 17th. Here, therefore, we 
have two epochs of heat separated by an interval of about 
ten years. Had the series been carried out we should have 
had another warm epoch in the year 1878 or 1879, or in 
both, followed by unusual cold in 1880-81. 
It will be apparent, on examining the above fadts, that 
an unusually warm summer does not stand alone. As a rule 
it is preceded or followed by mild winters, and may be 
regarded as a culminating point from which the temperature 
descends on either side through a total space of about two 
years. With exceptionally cold and prolonged winters the 
case is inversely similar ; they are either ushered in or suc- 
ceeded by chilly, wet summers, and the depression of tem- 
perature is rarely limited to a single season. Thus the 
summer of 1862, though not absolutely frosty like its pre- 
decessor, was still cool, and not until 1863 had we any true 
summer weather. 
Much of this becomes intelligible if we remember that 
the character of the seasons in Western Europe is more 
immediately at least determined by the conflict of the two 
great atmospheric currents, the polar and the equatorial. 
In what may be called average years the opponents are 
about equal in strength, and have their battle-ground over 
the British Islands. Hence the proverbial fickleness of our 
climate, the cloudiness of our heavens, and constant possi- 
bility of warm weather at Christmas, or of frost in summer 
or early autumn, according as one or other of these aerial 
rivals wins a temporary advantage. Sometimes, however, 
though rarely, the equatorial current gets decidedly the 
upper hand, as in 1868, and retains it for a year or more. 
In this case the battle-ground is transferred to Norway, 
whilst we are deeply and continually immersed in southerly 
winds. The weather then is not merely warm, but dry, for 
these winds do not deposit their moisture unless chilled by 
the near proximity of a polar current of air. More com- 
monly, however, as in the present season and in 1861, the 
polar current gets and maintains a long superiority. The 
conflict is then transferred to Spain, and we are completely 
plunged in icy winds. If a southerly or south-westerly air 
blows for a short time, its stock of moisture is immediately 
precipitated by contact with the chilled earth or by polar 
