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 that the increase of temperature is especially marked for the months of November, December and January.

The winter temperature of Great Britain is so distributed that for invalids a journey southward is of little benefit, unless directed at the same time towards the W.; and as the W. temperatures from Wales to Shetland are uniform and equal to those of Sussex, it is only the south-western counties that present maximum temperatures. These are 4° in excess of the West of Scotland and Sussex, and 6° in excess of the East of Scotland and England.

The S. W. of Ireland may be compared with the corresponding part of England.

The greater the range of temperature, comparing summer with winter, the greater, as a rule, is the death-rate. Hence the greater mortality of England compared with Scotland.

The mean annual temperature falls on an average about 1° for every increase of 300 feet in the height above the sea.

When the atmosphere is highly charged with vapour, the escape of heat by radiation is obstructed, and the temperature falls but little during the night; but when the quantity of vapour is small, radiation is less impeded, and the temperature falls rapidly.

Similarly in the day-time; the prevalence of vapour obstructs the passage of the solar rays, and the temperature rises slowly; but the absence of vapour causes a rapid rise.

The comparative absence of aqueous vapours in mountainous districts, facilitating