On the Tails of Comets. 35 



Not having seen any notice of this novel and safe method of 

 blasting in yonr excellent journal, induced me to send you these 

 few remarks. 



I believe I am the first in Ireland that applied the galvanic bat- 

 tery instead of the fuze in blasting. 



Art. V. — On the Tails of Comets ; by William Mitchell, of 

 Nantucket, Mass. 



There is perhaps no department of astronomical science, con- 

 nected with the solar system, of a nature more interesting than 

 that of Comets, and certainly no one which has so nearly defied 

 the researches and the reasonings of the astronomer. Aside from 

 these bodies, if such they may be called, the greater and the 

 lesser lights have been subjected to rigorous weight and measure, 

 and the solar system is emphatically the beaten way of the as- 

 tronomer. Comets however have presented difficulties so insu- 

 perable, that in latter times the subject seems to have been nearly 

 abandoned in despair; and armed as the present age may be 

 against the horrors of superstition, a cometary appeai'ance as im- 

 posing as that of 1680, or even of the less threatening aspect of 

 that of 1744, would create no small degree of uneasiness in some 

 hearts of the stoutest mould. When Dr. Olbers announced that 

 a portion of the earth's orbit would be involved in the nebulous 

 atmosphere of Biela's comet in 1S32, one half at least of the 

 civilized world quaked with fear. Notwithstanding the alluring 

 promise held out to the modern student by the glories of siderial 

 astronomy, nothing can justify a neglect of phenomena which, by 

 a close investigation, might result in contributing so much to the 

 tranquillity of the world. Impressed forcibly in my youth by the 

 beautiful appearance of the comet of 18Q7, and, at a riper age, 

 with those of 1811, 1819, 1825, and 1835, visible to the naked 

 eye, and with others, seen at various periods by telescopic aid, I 

 have been led frequently to reflect on the probable nature and 

 physical properties of these erratic objects, and especially on that 

 distinguishing appendage which by common consent is denom- 

 inated the tail. In looking over the history of comets, and no- 

 ting the explanation of the trains (with which they are for the 



