34 



REPORT — 1856. 



over Bordeaux, where the wind is light. At Versailles the thermometric curves show 

 that the warm S.W. wind raised the temperature 12° C, and the cold N.W. wind 

 afterwards produced a corresponding depression. These curves are good types of 

 the general actions of the barometer and thermometer during the transit of a cyclone. 



1856. — In order to determine as accurately as possible the various phases of the 

 weather in Great Britain during the months of April and May, 1856, I have con- 

 structed the curve of barometric pressure, and the curves of maximum and minimum 

 temperature (the latter on the scale of 20° F. to an inch) from the observations 

 during these months, at eight stations of the British Meteorological Society; viz. 

 Elgin, Anstruther, and Makerstoun, in Scotland ; Stonyhurst, Wakefield, Canter- 

 bury, and Teignmouth, in England ; and Lampeter, in Wales. From these I have 

 selected to accompany this paper the curves for Wakefield, where observations are 

 made night and day at equal intervals of six hours, and those for Elgin and Teign- 

 mouth, the extreme stations to the North and South respectively. 



These curves indicate, as in the case of the inundations of 1846, a succession of 

 cyclones, of storms of wind and rain, producing floods of increasing height and 

 violence, until the culminating disastrous inundations at the end of May and in the 

 beginning of June. 



Two cyclones, either of enormous extent or of slow progressive motion, occupy 

 the whole month of April. The first ended about the 15th, and caused great floods 

 in the Garonne, and other large rivers of France. The second cyclone had passed 

 over by the 2nd of May. An abrupt depression of the mercury, accompanied by 

 heavy easterly gales, shows the passage of a cyclone between the 3rd and 8th of 

 May ; the central track lying to the south of Britain. From the 8th to the 20th of May, 

 a deep cyclonic depression occurs. Physical phsenomena happen during this period, 

 which frequently characterize the passage of cyclones in tropical countries. On the 

 10th of May there was a heavy earthquake at Saint Rabier, in the canton of Terras- 



