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V. On the comhined Jetton of Water and Charcoal in oxidizing 

 iMelals. By Thomas Gill, Esq. 



To Mr. Tllloch. 



Sir, — A FACT stated by Dr. William Henry in the last Num- 

 ber of Thomiison's Annals, of the oxiding of a metal (cast iron) 

 by the combined action of charcoal and steam ; brings to my 

 mind a similar effect which occurred to our ingenious acquaint- 

 ance Mr.T. T. Hawkins, several years since; who, in employing 

 powdered charcoal placed between two perforated leaden plates, 

 for the purpose of tiltering water, found the water had become 

 considerably impregnated with lead, which led him to take the 

 filtre to pieces, when it appeared that the joint action of the wa- 

 ter and charcoal had converted much of the lead into a white 

 oxide, which interspersed with the charcoal, occupied the en- 

 tire space between the plates, and therefore he was under the 

 necessity of laying them aside, and substitutuig others in their 

 places iiot liable to that defect ; by which means he perfectly 

 attained his object, that of employing charcoal as a filtering 

 medium, for which, owing to its great porosity, it is admirably 

 adapted. I am, with much respect, sir. 



Your most obedient servant. 



No. 83,'St. .Taincs's Sfrcet, ThoMAS GiLI,. 



Loii(loi), J;iii. 10, 181.'). 



VI. Account of a Fall of XJranohtes (A'eioUtts) near J gen. 

 By M. Dii Saint Amans*. 



Wn the 5th of September 1814, a few minutes before mid -day, 

 the wind being northerly, and the sky perfectly serene, a violent 

 detonation was heard in the communes of Montjjezat, Temple, 

 Castelmoron, and Montclar, situated in the first, second, and 

 fourth (irrondiswme7)s of the deptirtrnent of the Lotand Garonne. 

 This unusual detonation was immediately followed by three or 

 four others at an interval of half a second successively; and 

 finally, by a rolling noise at first resembling a discharge of mus- 

 ketry, afterwards the rolling of carriages, and finally, that of a 

 large building falling down. These detonations, which took 

 place towards the centre of the department, were heard with 

 more or less intensity within a circle of several leagues. Thus 

 at Agen, four leagues off, they were sufficiently strong to 



* Annidca dc t liimic, tome xcii. p. 25. Oct. 1811. 



B 4 alarm 



