Miscellanies. 395 



fears of the unknown, tlie comets will do exceedingly well : but 

 earthquakes, the possibility of new volcanoes, &c., should not be 

 entirely neglected ; and the theory of epidemics being caused by 

 comet matter fallino- down from the hiofher air should be cherished. 

 Athenaeum. 



Basalt and Tufa. 



There is reason to believe that much confusion in geology has 

 resulted from want of careful attention to the distinction of truly 

 molten rocks fi-om consolidated volcanic ashes, which, as in the 

 case of the Palagonites of modern volcanic regions, are often re- 

 consolidated by aqueous infiltration into rocks even harder than 

 those cooled fi-om a state of fusion. An interesting experiment 

 on this subject is quoted in the Journal of the Geological Society 

 of London, No. 46. (Expt. by A. Beusch Lunt, and Berne Johr,, 

 1855, p. 597). Basalt (sp. grav. 2.877) was ground in water to 

 fine powder, and allowed to remain for some months in a glass 

 cup. It became a hard stone ; in the centre black and waxy, ex- 

 ternally less dense and grey. Exposed for some time to air, it 

 exhibited an appearance of carbonate of potash. The specific 

 gravity of the nucleus was 2.1588 ; that of the external portion 

 2.423. It is probable that, in this case, hydrated silicates were 

 formed out of the basalt ; and it would be interesting to have 

 similar trials made with igneous rocks of known composition, and 

 to compare the results with the actual composition of trappean 

 rocks. D. 



Native Copper in Scotland. 



The occurrence of native copper in Scotland was noticed in a 

 paper, recently read before the Philosophical Society of Glasgow 

 by J. Bryce, Jr., F. E. S. 



" The metal occurs at Barrhead in a state of perfect purity, in 

 the Boylestone quarry, about a quarter of a mile north-west of the 

 railway station. The rock is a coarsely crystalline greenstone, a 

 member of the trap series which forms the Fereneze hill ranges, 

 erupted through, overlying and much altering the lower marine 

 coal series which occurs in that district. Through this rock the 

 metal is irregularly distributed in large thin plates, usually at- 

 tached firmly to the rock, and also coating its surface in broad 

 films, as if laid on by the electrotype process. It occurs also in 

 large lumps, and in flattened dendritic masses. Its origin was 

 ascribed by Mr. Bryce to the circulation of electric currents 



