314 Subscription proposed for Minerals. 



tion of oxygen gas with hydrogen gas in Volta's eudiometer; hut 

 it is circumscribed in its breadth, and extends to the bottom of 

 the vessel. We cannot compare it to anv thing so well as to 

 those flashes of fire vvliich dart through the cloud's in a storm. 



" When the bladder bursts of itself before having made an 

 entire vacuum, the light which is then emitted is weak, reddish, 

 and appears at the bottom of the vessel only. In general it is 

 the stronger and more ainmdant as the vacuum is more perfect 

 ivhen the bladder is broken. When the rupture of the bladder 

 takes place simultaneously at two different points, we see two 

 luminous points : in the contrary case we see one only. 



" May not the lightning which precedes the thunder be pro- 

 duced in the same way?" 



SUBSCRIPTIOX PROPOSED FOR MINERALS. 



The Journal des Mines for May last contains the following 

 notification : "The zeal with which the study of fossils and petri- 

 factions has been prosecuted for several years, has suggested to the 

 members of the Bureau de Mineralogie established at Hanau 

 in Wetteravia, the idea of forming systematic collections of petri- 

 factions, which they offer to furnish in successive portions at 

 stated periods; and they flatter themselves, in consequence, with 

 obtaining the approbation and support of amateurs and the 

 learned. These collections, it it said in the German Prospectus 

 published on the subject, will present not only in isolated in- 

 dividuals all the fine remains of the organic world, the greater 

 part of which are lost to us, but they will exiiibit as perfect a 

 view as possible, in pieces well characterized and carefully se- 

 lected. Scientific travellers will be sent into countries which 

 are richest in petrifactions, and will thus procure the means of 

 supplying gentlemen who form collections, with series as com- 

 plete as possible. 



*'But as an enterprise of this kind requires a considerable ad- 

 vance of money ; and as it is desirable, before procuring from far 

 distant countries, such as Italy, Switzerland, and France, tlie ar- 

 ticles which have been already ordered, that a deposit should be 

 made onwhich rehancecan be placed, the plan of a subscription 

 has been preferred. 



"Every delivery will be composed of 50 specimens of the size of 

 two inches by four, for petrifactions still adhering to the matrix, 

 or a proportionate number of isolated specimens when the petri- 

 faction itself is within or beyond this size : and the jirice of each 

 delivery will be six reichs thaler (about 1/. I5. English) to sub- 

 scribers, and nine rix dollars (or 1/. lb. 6(/.) to non-sub- 

 scribers, 



" The 



