18 REPORT 1839. 



in direction. A deflection in the wind, in the opposite direction to 

 what is now described, sometimes takes place, but not so frequently. 

 As to whether these deviations are in regular curves, and are segments 

 of large circles, or merely deflections in the course of the currents 

 caused by some peculiarity in the situation of the places, or whether 

 it be our insular position that modifies the currents, I cannot venture 

 an opinion. The course of the currents is, as might have been ex- 

 pected, much more steady at Plymouth than at Birmingham. Thus 

 on the 29th, 30th, and 31st of January last, the wind commenced at 

 due west, and veered at a perfectly even rate round to the north : while 

 in Birmingham the course of the current was exceedingly unsteady, 

 and veered round one half the compass, in Plymouth it only moved 

 one quarter. This, among many other instances which I could bring 

 forward, shows that great care should be taken in the selection of sta- 

 tions for making observations concerning the course of the main cur- 

 rents of the atmosphere, which ought to be our principal object in the 

 first instance ; for we must not hope, for a long time to come, to lay 

 down the minor fluctuations by which the greater ones are modified. 



I shall conclude with a few remarks on the great storm of the 6th and 

 7th of January last (1839), that committed such dreadful ravages in this 

 country, and trace its probable course and action. In addition to the re- 

 cords obtained by the anemometer at this place and at Plymouth, I have 

 collected what information I could concerning the nature and extent of 

 this storm from many parts of the British Isles. A careful analysis of these 

 strongly leads me to the opinion that this was a small but violent rotatory 

 storm, moving forward at the rate of about thirty to thirty-five miles per 

 hour. The diameter of the rotating portion I am not prepared to give, 

 nor do I consider it at all certain that it could be ascertained, as it 

 seems likely that the revolutions were not in contact with the earth. The 

 tendency of this eddy, or violent whirling of the air, would, of course, 

 be to produce a vacuum in the centre. The air that forms the eddy 

 being constantly thrown off" in a slight degree spirally upwards, and 

 dispersed in the upper portion of the atmosphere, the effect of this 

 would be to produce a strong current upwards. Now, supposing 

 this large eddy to be perfectly stationary, there would be a rapid rush 

 of air towards it from all sides, which would be drawn up and 

 thrown off through this rotating circle, and dispersed with amazing 

 rapidity above : but as it is moving on with great velocity, the air that 

 is in the advance of the storm is not sensibly affected until the whirl is 

 close to it ; while in the rear the motion of the air is greatly increased ; 

 first, by the tendency of the air to rush into the great vortex of the storm ; 

 and, secondly, by the motion onward of the vortex itself. This vortex 

 or revolving column would increase in size upwards, so as somewhat to 

 resemble a funnel ; it would in fact be similar in its shape and action to 

 an immense water-spout ; whether it was vertical or not is entirely a 

 matter of conjecture, bat I should consider it probable that it would 

 incline in the direction that the storm was moving ; namely, to the 

 N.E., and that it was an upper current that carried it in that direction. 

 The greatest intensity of the storm in England was evidently across 



