286 Col. Beaufoy's Astronomical Observations. [Oct. 



of gas from the wire. It is, in fact, precisely the experiment 

 described in Art. 25, and has nothing whatever to do either with 

 the floating fragments, or with any hydrogen they may be dis- 

 charging at the time, farther than that their contact serves to 

 furnish potassium to the mercury. 



63. It is needless, therefore, to push this examination further, 

 as all the phenomena observed by Mr. S. are only particular 

 cases of those I have described. With regard to the radiant 

 hydrogen producing currents by its impulse, I would ask how it 

 happens that currents are producea (when the positive pole is 

 placed in contact), while a thick and tough coat of oxide 

 covers the whole surface ; and, one would think, must effectually 

 defend it from the action of the hydrogen. Yet we have seen, 

 in Art. 18, that the currents continue their course under this 

 crust ; and it will hardly be contended, that the hydrogen finds 

 a passage between the oxide and the metal. 



London, Jan. 13, 1824. J- F- W. H. 



Article XII. 



Nitric Ether. By Mr. Whipple. 



(To the Editors of the Annals of Philosophy.) 



GENTLEMEN, Elaborately, London, Scj)t. IT, 1824. 



Since to give my opinion on the directions given by Dr. Ure 

 in his Chemical Dictionary, for conducting a retort distillation 

 of nitric ether, would be yhuwa. etc Aflrjvaj ko/ai^-iv, 1 shall feel 

 obliged if favoured with an insertion of the following question : 

 Whether the directions for the management of a glass retort in 

 forming nitric ether, be correctly stated in Dr. lire's Chemical 

 Dictionary 1 



I remain, Gentlemen, your most obedient servant, 



G. Whipple. 



Article XIII. 



Astronomical Observations, 1824. 

 By Col. Beaufoy, FRS. 



Busbey Heath, near Stanmore. 

 Latitude 51° 37' 44*3" North. Longitude West in time 1' 20-93". 



Occultations of stars by the moon. 



Sept. 4. Immersion of a small star 19" 10' 54'0> siderial Time. 



Sept. 15. Immersion of u small st*r 3 28 4 b '<«> 



