1824.] Scientific Notices— Miscellaneous. 75 



In the rock at Beverly, there is a great tendency of the com- 

 ponent parts to assume regular crystalline forms, and a few per- 

 fect crystals of green felspar have been obtained. 



Phosphate of Lime.— I have lately found a few pretty distinct 

 crystals of phosphate of lime near the village of Stow, in this 

 state The crystals are disseminated in rolled masses of a 

 coarse grained granite. They are portions of hexeedral prisms, 

 of a greenish-white colour. The fracture in the direction parallel 

 to the base of the prism is distinctly foliated, and the powder 

 phosphoresces on burning coals. 



The same granite contains well defined crystals ot beryl, and 

 here and there a small crystal of tourmaline. 



Andalusite.— This mineral I found in a rolled mass ot white 

 quartz, in small imperfect four-sided prisms, near Lancaster. 

 The colour is a reddish-brown. 



Spodumen.—A notice of this mineral has lately been published 

 in the Journal of the Academy of Nat. Sci. of Philadelphia. 

 I have visited the locality at Sterling, and find it very abundant. 

 The principal rock in which it occurs is a compound of quartz, 

 mica, and spodumen, weighing probably about thirty tons. It 

 may be called spodumen rock. 



Cleavelandite occurs in small quantity at Sterling.— (Boston 

 Journ. of Philos. and the Arts, No. 6, May, 1824.) 



Miscellaneous. 



8. On the Cause of the Rotatory Motion of Camphor in Water. 



(To the Editor of the Annals of Philosophy.) 

 SIR, 

 If your Cambridge correspondent E. A. (see Annals of last 

 month) will look at page 51 of the first volume of Nicholson s 

 Journal, 8vo. series, he will find that he is mistaken m supposing 

 that no cause has been hitherto assigned for the rotatory motion 

 of a particle of camphor when placed on the surface of water. 

 Several eminent men, as he will there see, have turned then- 

 attention to this curious subject, amongst whom are Benedict 

 Prevost, Venturi, and Caradori ; and the results of their experi- 

 ments will, I dare say, both interest and amuse your friend 

 E. A. The paper alluded to is an abstract of M. B. Provosts 

 inquiries on the subject, by M. Biot, who considers that we 

 may infer from them, as an established fact, that " camphor is 

 moved upon the surface of water by the effect of the emission ot 

 the particles which compose it ; an emission that becomes per- 

 ceptible to our senses by the smell which it produces, and by 

 the repulsions which it exercises against small bodies floating 

 upon the surface of water. As the effect resulting from these 

 different impulses does not pass through the centre of gravity ot 

 the piece of camphor, this centre has a progressive motion, and 

 the body revolves round it," fcc. E. A. conceives the rotatory 



