pro CORRESPOI^ENTS. 



Papers will appear in our next, from Mr. Jarae« Hall, Dr. Asa Gr 

 vel, Dr. Locke, Dr. H. C. Perkins, Prof. G. R. Perkins, Prof. J. W. titll 

 Lawrence Smith, Dr. T. M. Brewer, Mr. S. S. Haideman, Mr. H. C. Lea, Mr, J. 

 H. Blake, and others. 



'• A Constant Reader" requests of us " some practical description of the Daguerre- 

 otype." We would williiigly gratify him, but such has been and is stiH the rapid 

 advance of the processes, and such the variety of manipulations, that we must wait 

 for a more advanced and mature state of this elegant art. We refer him to an ac- 

 count of the process published in this Journal, Vol. xt, p. 137. 



Papers have been received from Prof. Strong, Dr. Springer, Dr. Van Rensselaer, 

 Mr. F. G. Woodwards, Dr. J. T. Plummer, Mr. Thos. L. Knapp. 



Prof. Dewey's article, promised in our last, has not been received Dr. Locke's 

 could not be published for want of the plates illustrating it. Dr. Gray's article was 

 postponed with his consent to January. We owe apologies to a number of valued 

 correspondents for our unfulfilled obligations; the somewhat unexpected insertion of 

 Prof. Hitchcock's Address before the Associated Geologists, has excluded a number 

 of short communications which wo had hoped to insert. It is in vain that we en- 

 deavor to clear our docket of valuable papers ; and our friends must be charitable 

 enough to believe that the delay which sometimes occurs, is the result of necessity 

 and not of intention. 



Reply of Sir Mich-ael Faraday to Dr. Ha»e.— We have to regret, that a 

 letter addressed to us by Sir Michael Faraday, and intended for this Journal, has 

 been mislaid. In substance, however, its object was to decline a farther public dis- 

 cussion of the points at issue — referring instead to the memoirs already published, 

 or which may hereafter appear on the subject. We have learned with regret, that 

 the health of Sir Michael Faraday has declined under his arduous labors, and that 

 relaxation has become indispensable to his restoration. His friendly antagonist. Dr. 

 Hare, being now abroad in Europe for similar reasons, we can only wish to them 

 both a speedy recovery of health, to enable them to resume their important and 

 successful researches. 



The titles of communications and of their authors, must be fully given. 



Authors should always specify at the head of their MSS. the number of extra 

 copies of their communications which they may wish to have printed. 



Return proofs, not to be sealed, or inscribed with any thing except corrections. 



Notice always to be given when communications sent to this Journal, have been, 

 or are to be, published also in other Journals. 



Erratum. — On the Plate to Prof. Bailey's article, for Desmidaeeae, read Desmi- 

 diaeete. 



NOTICE. 



The public are cautioned not to make payment for subscriptions to this Journal, 

 except to such persons as are authorized to receive it. This work is sent Post paid. 

 See the Prospectus on the third page of this cover. 



