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SCIENTIFIC INTELLIGENCE. 



METEOROLOGY. 



1. Falling Stars. — The following letter of Sir John Herschel to the 

 Editor of the Athenceum on the periods of the falling stars will in- 

 terest our readers : — 



Sir, — The bright moonlight of the 9th inst, having prevented my ob- 

 taining satisfactory observations of the meteors, to whose periodical re- 

 turn on the 9th and lOtli of this month Prof. Quetelet has drawn much 

 attention, as being more regular than the display of the 12th and 13th 

 November, allow me, in place of observations for the current year, to offer, 

 as my contribution to our stock of knowledge of the subject, the follow- 

 ing incidental mention of such an occurrence, which occurs in Sir W. 

 Hamilton's account of the great eruption of Vesuvius in August 1779, 

 printed in the Transactions of the Royal Society, vol. 70, which will be 

 read with the more interest, the periodical nature of the phenomena be- 

 ing then unknown, and its occurrence being ascribed by him to some 

 local electrical agency, developed by the volcanic ejections. 



'' August 9. 1799," after describing the phenomena of the eruption 

 during the day till seven o'clock at night, " when all was calm," Sir Wil- 

 liam Hamilton goes on to say, " it was universally remarked, that the 

 air this night, for many hours after the eruption, was filled with meteors, 

 such as are vulgarly called falling stars. They shot generally in a hori- 

 zontal direction, leaving a luminous train behind them, but which quickly 

 disappeared. The night was remarkably fine, starlight, and without a 

 cloud. This kind of electrical fire seemed to be harmless and never to reach 

 the ground, whereas that with which the black volcanic cloud of last night 

 was pregnant, appeared mischievous, like that which attends a severe 

 thunder-storm." The meteors of August 9. 1840, in so far as I observed 

 them, radiated almost without exception from a point in the heavens 

 very near the star y (Gamma), in the constellation Perseus, which is al- 

 most coincident with the point (near the star /3 Camelopardali) from which 

 I observed them to emanate on the 10th August 1839. Facts of this 

 nature appear most decisive in favour of the opinion, that a zone or zones 

 of these bodies revolve about the sun, and are intersected by the earth 

 in its annual revolution. 



(Signed) J. F. W. Hkrschkl. 



COLLINOWOOD, Aug. 15. 1831. 



GEOLOGY. 



2. Galvanism and Polarity as connected with the origin of the 

 structure of rocks. — Whenever we meet with rocks admitting of the 

 preservation of organic remains, the number of these decreases as we 

 descend in the series, till we arrive at a period when the physical 



