282 British Association for the Advancem&tit of Science. 



with Col. Reid's charts, particularly impressed him : the first was 

 the curious parabolic shape of the courses denoting the progress 

 of these storms, so well calculated to give unfailing directions as 

 to the nature and course of a storm, when accidentally encoun- 

 tered at sea ; as the sailor had only to consider the parts of these 

 curves in which he was placed, and the veering of the wind, and 

 he had almost placed before him a chart of the hurricane. He 

 next threw out the suggestion for Col. Reid's consideration, 

 whether the Gulf-Stream would not perhaps give a clue to the 

 direction of these curves, as so large a body of comparatively 

 warm water must most materially tend to heat the air above it, 

 and thus occasion disturbances of atmospheric equilibrium. Col. 

 Reid had stated that he had no theory : in this no doubt he was 

 judicious as an observer ; but yet, in the present assembly, a the- 

 ory, if it served no better purpose, helped memory, suggested 

 views, and was even useful by affording matter for controversy, 

 which might produce brilliant results, by the very collision of in- 

 tellect. In the second place, he remarked, that in the southern 

 hemisphere, the oscillations of the barometer, which were in an 

 opposite direction to those of the northern, afforded a strong con- 

 firmation of the correctness of Col. Reid's views. These revolv- 

 ing hurricanes reminded him, that on discharging a great gun 

 unshotted, the mouth of which had been previously greased, a 

 beautiful ring of smoke is formed, which passes to a considerable 

 distance with much permanence, but constantly enlarging in di- 

 ameter : upon attending closely to this, every part of the ring will 

 be found to be in rapid revolving motion, thus exhibiting to the 

 eye a hurricane in miniature, performing its evolutions. As to 

 Mr. Espy's theory, though he considered it ingenious, yet he did 

 not see how it v/as tenable against the indications of the barom- 

 eter ; for, unquestionably, if a large body of air were to set on 

 every side inwards, towards a central ascending column, the ne- 

 cessary effect would be an increase of weight of the entire baro- 

 metric column : but there was even stronger evidence against it ; 

 for if the air acquired any thing of a gyratory motion, on the 

 principle of the vis viva, the rapidity of gyrations should increase 

 enormously as we approach the center of the column ; just as we 

 see the opera dancers, in the pirouette, increase the rapidity of the 

 evolution as they diminish the circuit ; and so we find in the in- 

 dications of the facts detailed by Col. Reid, regarding the hurri- 



