TO CORRESPONDENTS, 



The Rev. B. Powell's Paper on the Interference of Light will be 

 inserted in our next. 



A paper on a new Anemometer has been received j and also Commu- 

 nications from Mr. Meikle, Mr. S. Shakpe, Mr. Blackwall, the 

 Royal Geological Society of Cornwall, and the Belfast Na- 

 tural History Society, all which will meet with speedy attention. 



Mr. Fearn's Works on Cerebral Vision and Color Images in the. 

 Brain, have been received for review. 



Anxious to render the General Analytical Index to the first 

 ten volumes of our New Series as complete an analysis as possible of 

 the contents of the work, the care and attention requisite for that pur- 

 pose will, we find, prevent its being ready until the 1st of February next, 

 •when it will be published as an additional Number of the Phil. Mag. and 

 Annals. This supersedes the necessity of occupying any of the pages of 

 the present Number with a separate Index to Volume X. with which the 

 General Index will be arranged to bind. 



Simplex is unavoidably deferred till our next Number. 



WESTERN LITERARY and SCIENTIFIC INSTITUTION, 

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ON Thursday, December 8th, Mr. E. W. BRAYLEY, Jun. A.L.S., 

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MATHEImATICAL and PHILOSOPHICAL BOOKS. 



S. MAYNARD, 



Bookseller, 91, Crown-Court, Dorset- Street, Fleet-Street, 



D EGS leave to inform the Nobility and Gentry, that he has constantly 

 JJ on Sale a valuable Collection of scarce Mathematical and Philoso- 

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Catalogues may be had, gratis, upon application as above. 



As S. M. devotes the chief part of his attention to the procuring of 

 scarce and valuable Books in the above Sciences, he trusts that if 

 honoured with the Orders of scientific Gentlemen, he shall be able to 

 execute them with entire satisfaction. 



THE POLYTECHNIC LIBRARY. 



The Second Volume of this Work, containing 360 pages of Letter-press, 

 and 35 Wood-cuts, Price 4s. in Cloth, will be published on the 1st of 

 December, viz. 



rpHE DOMESTIC CHEMIST; comprising Instructions for the De- 

 J. tection of Adulterations in nearly three hundred of the most 

 important Preparations employed in Domestic CEconomy, Medicine, and 

 the Arts. To which are subjoined, the Art of Detecting Poisons in 

 Food and Organic Mixtures, and a Popular Introduction to the Principle* 

 or Chemical Analysis. 



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