( li ) 



The author then stated the grounds for his coming to the conclusion 

 that when the Fulminate of Mercury and the Perrocyanide of Potas- 

 sium react on each other, that there is at first formed, amongst other 

 products, the double neutral Fulminates of Iron and Potassium by the 

 following reaction : 



iSg CiN^O^ + K^Fe {Cy\ = TeKo {a,No0.y^ + 2 ECy^ + 2 KCy, 



and that this double neutral salt subsequently, either by the action of 

 acids, heat, or other agencies, passes into the acid Fulminate of Iron, 

 thus developing the red coloration observed. 



After referriag to the instability and other characteristic properties 

 of this salt of Iron, the author stated that it was likewise developed 

 by the action of the Ferricyanide of Potassium (Ped Prussiate of 

 Potash) on the Fulminate of Mercury, and that it and the Ferricyanide 

 of Potassium, even at the ordinary temperature, gave rise to, but more 

 slowly, the formation of the red acid salt ; and lastly he stated that 

 the same compound was formed where the Fulminate of Silver had 

 been used instead of the mercurial salt, and that it was probable that 

 some of the other Fulminates would act in a similar manner. 



[This paper will be published in extenso.~\ 



Dr. Doberck, Astronomer at Col. Cooper's Observatoiy, Markree, 

 County SHgo, read a Paper " On the Fu'st Comet, in 1845." 



[This memoir will appear as Part 12 of the Transactions of the 

 Academy.] 



Bessel has remarked that the astronomers of a certain age will only 

 have completed their work when all the observations of the heavenly 

 bodies which have been previously recorded have been as nearly as 

 possible represented by calculation. It is quite in conformity with 

 this remark that Professor Bruhns of Leipzig, has (in the Journal of 

 the Astronomical Association of Germany) called the attention of 

 astronomers to a number of comets whose orbits could be more 

 accurately ascertained when all available observations were taken into 

 account. The present Paper contains the definitive elements of 

 Comet I 1845, being the fifth of the comets determined by the author. 



As far as possible, the whole number of about 250 observations 

 has been compared with a system of elements derived from the com- 

 parison of all the hitherto published orbits. By this comparison aU 

 the smaller corrections were applied, including the perturbations 

 caused by Jupiter and the Earth, the action of the other planets- 



