524 PHILOSOPHICAL TRANSACTIONS. [ANNO 1784. 



joining them may cut the path of the meteor at right-angles, and that, at its 

 greatest elevation, it may appear from both of them about 4 5° above the horizon, 

 on opposite sides of the zenith. Dr. B. laments that most of the observations in 

 his possession of the meteor of August 18, give its altitude by estimation only; 

 vet their correspondence with each other may gain them a degree of credit, to 

 which, if single, they would not be entitled. Dr. B. here relates 8 or Q accounts 

 of the height and motion of this meteor, from which he calculates its perpendi- 

 cular height above the earth's surface in most of these instances, and finds they 

 run from 57 to 60 miles in height. And further observes, this agreement of the 

 different altitudes is nearer than could be expected ; and therefore we may safely 

 conclude, that it must have been more than 50 miles above the surface of the 

 earth, in a region where the air is at least 30000 times rarer than here below. 



§ 6. That a report was heard some time after the meteor of the 18th of 

 August had disappeared, is a fact which rests on the testimony of too many wit- 

 nesses to be controverted, and is conformable to what has been observed in most 

 other instances. In general it was compared to the falling of some heavy body 

 in a room above stairs, or to the discharge of one or more large cannon at a dis- 

 tance. That rattling noise, like a volley of small arms, which has been remarked 

 after other meteors, does not seem to have been heard on this occasion. From 

 a comparison of the different accounts, it appears as if the report was loudest in 

 Lincolnshire and the adjacent countries, and again in the eastern parts of Kent ; 

 in the intermediate places it was so indistinct as generally not to have been 

 noticed, and all observers of credit in Scotland deny that they heard any thing of 

 the sort. If this report then be connected with the bursting of the meteor, it 

 would seem as if that sound was produced two separate times, namely at the first 

 explosion over Lincolnshire, and again when it seemed to burst soon after enter- 

 ing the continent. Ingenious men have availed themselves of this sound, to cal- 

 culate the distance and height of meteors ; and the exactness attained by this 

 method, in the computation of the late fire-ball from the report heard at 

 Windsor, is very remarkable ; but in general the accounts disagreed so much, that 

 it would have been impossible to conclude any thing from them. Besides the re- 

 port as of explosions which was heard after the meteor, another sort of sound was 

 said to attend it, more doubtful in its nature, and less established by evidence, viz. 

 a kind of hissing, whizzing, or crackling, as it passed along. That sound should 

 be conveyed to us in an instant from a body above 50 miles distant, appears so 

 irreconcilable to all we know of philosophy, that perhaps we should be justified in 

 imputing the whole to an affrighted imagination, or an illusion produced by the 

 fancied analogy of fireworks. The testimony in support of it is however so con- 

 siderable, on the occasion of this as well as former meteors, that Dr. B. cannot 



