316 Scientific Notices — Miscellaneous. [Oct. 



has but one cleavage which is parallel to the longer diagonal of 

 the prism. The sides and angles of the crystals are frequently 

 rounded. 



Its hardness exceeds that of quartz: even topaz may be 

 scratched by some of the specimens. It is translucent on the 

 edo-es, and in small fragments ; it is brittle, and easily reduced 

 to powder. 



Its fracture, in the direction of the longer diagonal, is lamellar, 

 and displays a brilliant lustre ; the cross fracture is uneven and 

 splintery. 



It does not become electric either by heat or friction, nor give 

 any indications of magnetism. 

 Its specific gravity is 3*41. 



Before the blowpipe, it is infusible per se, and also when 

 heated with borax. 



The nitric, muriatic, and sulphuric acids, have no action on its 

 powder. 



From Mr. Bowen's analysis, sillimanitp, is composed of 



Water 0-510 



Silica 42-666 



Alumina 54- 1 1 1 



Oxide of iron T999 



Loss 0-714 



100-000 

 (American Journal of Science.) 



Miscellaneous. 



14. Extraordinary Extent of the Baise and Flannel Manufac- 

 ture at Rochdale. 

 " In the town of Rochdale and the adjacent villages, there 

 are manufactured every week, of flannels and baizes, about 

 20,000 pieces, of 46 yards each, making 47,840,000 yards per 

 annum. It is supposed that 17,840,000 yards are exported; 

 the remaining 30 millions of yards are consumed in the United 

 Kingdom, being an average of 1^ yard for each individual. 

 Some good flannels are manufactured in Wales ; a few coarse 

 ones at Keswick ; and some other towns and villages in the 

 kinodom. A few are manufactured on the Continent, and works 

 for that purpose are now erecting in America; but the whole of 

 the flannels manufactured on the globe, besides those manufac- 

 tured in Rochdale and its immediate vicinity, are not equal in 

 quantity to those made there. The price of flannels is 5d. to 3s. 

 per yard ; and the average may be stated at from 13d. to 14c?. 

 per yard ; so that the annual value of the manufacture may be 

 stated at about 3,000,000/. sterling. The wool costs fully one- 

 half of the wholesale selling price ; the oil, labour, and finishing, 

 8tc. constitute nearly the other half."— (Edin. Phil. Jour.) 



