Rain Gauge.' — Meteoric Stones. 153 



decomposition of water the two compounds are resolved into 

 chlorine, which proceeds towards the positive pole, and into 

 reduced mercury, which conjointly with hydrogen proceeds to 

 the negative pole. Water in stearn directed on the compounds 

 very much heated, takes from them the dry acid, and the mer- 

 cury remains reduced. This effect is much more easily produced 

 on the red hydrargyrio chlore than on the hlack. 



" 1 know not how far the announcement of Mr. Accum is well 

 founded* with respect to tlie metallization of charcoal; but in 

 the correspondence of the author of this discovery (M. Dobe- 

 reiner) with me, nothing of the kind is mentioned. I may not, 

 however, have received all his letters, owing to the war. His 

 colleague. Professor Kieser, with his pupils, like the rest of the 

 members of all the GeriTian colleges, is with the allied armies. 



" M. Dobereiner had already resolved silex in a great mea- 

 sure into carl)onic acid ; and some carbon proceeding from it 

 was sent, but it never reached me. According to Mr. Accum's 

 information, M. Dobereiner must have operated by the phos- 

 phuret of irou and li([uid alkali, which n)ust have produced phos^- 

 phuretted hydrogen gas, whereby tlie carbon will be hydro- 

 genated, and at the same time reduced, if this combustible does 

 not exist already without oxygen in carburetted iron. Tlie car- 

 bon is reduced in the alcohol of Lanijjadius, which by water is 

 regenerated into sulphur and into carbon, and requires for its 

 acidification more oxygen than its elements separated ; and the 

 sulphur is m( re or less reduced in the sulphuro-phosphorus, as 

 is prtoved by the water collected during the formation. A deto- 

 nation takes place, and hydrogen is disengaged." 



Bi-nsseN, Aui; 7. 1815. B. VaN MoNS. 



[To he coiitiiuicd.] 



To Mr. Tilloch. 

 Sir, — Iv your Magazine for May, page 387, I am requested 

 by .Mr. .lo'm Farcy sen. to ex])lain a mistake, or otherwise throw 

 some light on my extraordinary account of rain upon Blackstone 

 Edge in the nine months observation of IS 13, as inserted in one 

 of your former Numbers. The extraordinary notation of S6,()85 

 inches is certainly an error. My friend Mr. Leadbetter (the gen- 

 tleman who note-; the fall of rain upon Blackstone Edge) and \ are 

 convinced that the error arose from the rain, which was driven 

 against the outside of the funnel, getting access to the vessel under- 

 neath ; but vvliich fiiiice .laiiuary 1^14 has been effectually pre- 

 vented by a very sim|)Ie contrivance. On the outside of the rain- 

 fnmiel (which is made of copper, and surmounted with a cy- 

 lindrical rim two inches broad and six inclies diameter,) is sol- 

 di red, about the middle of the conical part, another piece of 

 * See vol. xlv. J). 150. 



conical 



