156 Scientific Notices — Miscellaneous. [Aug. 



14. Rare Minerals found in the Vicinity of Edinburgh. 



Within these few months beautiful specimens of deeply- 

 coloured prehnite have been found in Salisbury Craigs. In 

 several of these, the prehnite was associated with that kind of 

 datolite described under the name Humboldite by Mr. Levy. In 

 the basaltic rock of the Castle Hill, small but beautiful specimens 

 of radiated Wollastonite have been found. Many years ago, fine 

 specimens were got. The same mineral occurs occasionally in 

 h greenstone of Salisbury Craigs. — (Edin. Phil. Journ.) 



15. Discovery of Selenium in the. Volcanic Rocks of Lipari. 



Dr. Turner has just sent to us the following interesting notice, the 

 substance of which was communicated to him by Prof. Stromeyer. 

 " Prof. Stromeyer has lately discovered selenium under two differ- 

 ent forms, one of which is altogether new. On diluting some fu- 

 ming sulphuric acid, such as is made at Nordhausen from the 

 sulphate of iron, he observed that a solid matter separated from 

 the diluted acid, which, on examination, proved to be selenium. 

 One pound of the acid gave on dilution about a grain of selenium. 

 This substance has already been detected in some of the Bohe- 

 mian sulphuric acid ; and it is supposed that the acid in question 

 had been prepared in Bohemia. The second source of selenium 

 is in the volcanic productions of the Lipari Isles, among which 

 Prof. Stromeyer has lately discovered a native sulphuret of sele- 

 nium. He has mentioned neither the mineralogical character of 

 the new mineral, nor given an account of his chemical examina- 

 tion of it; but 1 hope soon to obtain from the Professor more 

 full information on the subject ; and shall then have great plea- 

 sure in communicating it to you. It appears probable from these 

 circumstances, that selenium is a more common production of 

 nature than is generally supposed ; and it may be anticipated 

 that it will frequently be found, whenever the attention of che- 

 mists and mineralogists in general shall be directed to the 

 subject." — (Edin. Phil. Jour.) 



Miscellaneous. 



16. Light and Heat from terrestrial Sources. 



Mr. B.Powell, FRS. has, during the last winter, been engaged 

 in a series of experiments on the light and heat emitted from 

 incandescent and burning bodies, in extension of those of MM. 

 Leslie, de la Roche, &c. The principal question investigated is 

 one with regard to the nature of the heating agents, which very 

 naturally arises from the results of the experiments just alluded 

 to : — viz. whether, of the effect from a luminous hot body, the 

 part intercepted by a glass screen is of the same nature as, or 

 different from, the part transmitted, (independently of the heat 

 acquired and radiated again by the screen). The result of 



