Intelligence and Miscellaneous Articles. 551 



veins and in rocks is proportional to the amount of their elevation 

 above the sea. 



Mr. Wallace then stated that Arragonite is produced only after 

 the strata are traversed by joints, and that the branched Arragonite 

 very rarely occurs, being found only in caverns and old workings. 

 Two of these caverns have come under his notice, and were de- 

 scribed in detail ; one of them is in the north vein of the Silver Band 

 Mine, and the other near one of the principal veins of the Dufton 

 Fell Mine. Finally he discussed the causes and conditions neces- 

 sary to the formation of this Coralloidal Arragonite, and came to the 

 conclusion that the theory of a circulation, through the pores of the 

 spar, of fluids holding its component parts in solution is the only 

 one that harmonizes with the varied phenomena observed in the two 

 caverns he had described. 



3. (l Notes on presenting some rhomboidal specimens of Iron- 

 stone, &c." By Sir J. F. W. Herschel, Bart., K.C.H., F.R.S., 

 F.G.S., &c. With a Note by Captain T. Longworth Dames. 



Most of these specimens came from a quarry at Clanmullen, near 

 Edenderry, King's County, and the remainder from the Collingwood 

 Quarry, in the Weald of Kent. The Irish specimens are siliceous, 

 containing some oxide of iron and a little manganese, and are 

 homogeneous throughout. They all agree in the sharpness of 

 definition and the exact parallelism and evenness of the flat surfaces ; 

 but, like those from the Weald, they are not constant in form or 

 size, and sometimes are very irregular in angle and in the parallelism 

 of opposite sides. The Wealden specimens, however, are all closed 

 boxes, each containing a rhomboid of hardened sandstone, the outer 

 case being highly ferruginous — in fact, the " Ironstone of the 

 Weald." Sir John Herschel endeavoured to account for the forma- 

 tion of the boxes, and Captain Dames added a Note stating the cir- 

 cumstances under which the Irish specimens occur. 



LXXV. Intelligence and Miscellaneous Articles, 



ELECTRICAL MACHINE WITH A PLATE OF SULPHUR. 

 BY M. RICHER. 



IT is known that M. Ste. -Claire Deville has found that if sulphur 

 is frequently remelted and suddenly cooled it is changed into 

 red sulphur. I have further noticed that in melting sulphur which 

 has thus crystallized several times, in special circumstances of cooling, 

 it assumes a kind of temper ; and this molecular condition appears to 

 be permanent. I have been able to obtain plates or disks of sulphur 

 2 to 3 centimetres in thickness and a metre in diameter. They 

 have a certain amount of toughness, but are somewhat more fragile 

 than glass ; but as they are very little hygroscopic, and can be ob- 

 tained at a very low price, they may be usefully employed in con- 

 structing frictional electrical machines. Several of these made more 

 than a year ago work regularly. — Comptes Rendus, January 30, 1865, 



