Page:Transactions of the Provincial Medical and Surgical Association, volume 2.djvu/96

 other respects the sky may be, precautions against the probable irruption of western showers, are seldom forgotten.

It may be stated, as a general fact, that the south and west winds are uniformly warm and soft, and the north and east winds uniformly cold and sharp. These unvarying effects on sensation are, as certainly, although in a lesser degree, indicated by the thermometer. In the winter and spring months, the north and east winds may be considered as having a temperature 6° or 8° lower than the south and west winds; and this is so constant a circumstance, that the change of the temperature is as regular as the change of the wind; that is, if the wind continues in its new direction for one or more days. The change of temperature is most remarkable when the wind is high, and, in this case, if the wind shifts suddenly, and continues still high, the change of temperature is very considerable in a short time. As this subject is curious and interesting, and has been too little attended to by writers on meteorology, I shall here give a short account of the more remarkable instances of these changes that occurred during the winter and spring months of two successive years, during my residence at Penzance.

1818. In January, at the beginning of a gale from the east, the thermometer was 45°, the following day it was 40°, and on the third, when the gale was at its height, it was 39°. In the same month, with a moderate wind from the west, the thermometer stood at 46°; on the following day this shifted a little to the southward of west, and increased to a pretty strong gale which lasted four days; during