ACKNOWLEDGMENTS TO CORRESPONDENTS, FRIENDS 

 AND STRANGERS. 



Remarks. — This method of acknowledgment has been adopt- 

 ed, because it is not always practicable to write letters, where 

 they might be reasonably expected j and still more difficult is it 

 to prepare and insert in this Journal, notices of all the books, pamph- 

 lets, &ic., which are kindly presented, even in cases, where such no- 

 tices, critical or commendatory, would be appropriate ; for it is often 

 equally impossible to command the time requisite to frame them, or 

 even to read the works ; still, judicious remarks, from other hands, 

 would usually find both acceptance and insertion. 



In public, it is rarely proper to advert to personal concerns ; to 

 excuse, for instance, any apparent neglect of courtesy, by pleading 

 the unintermitiing pressure of labor, and the numerous calls of our 

 fellow-men for information, advice, or assistance, in lines of duty, 

 with which they presume us to be acquainted. 



The apology, implied in this remark, is drawn from us, that we may 

 not seem inattentive to the civilities of many respectable persons, au- 

 thors, editors, publishers, and others, both at home and abroad. It 

 is still our endeavor to reply to all letters which appear to require an 

 answer; although, as a substitute, many acknowledgments are made 

 in these pages, which may sometimes be, in part, retrospective. — 

 Eds. 



SCIENCE. FOREIGN. 



On the composition of Chalk Rocks and Chalk Marl by invisible 

 organic bodies, from the observations of Prof. Ehrenberir ; with an 

 appendix touching the researches of MM Alcide and D'Orbi<my ; 

 by Thos. Weaver, Esq , F. R. S., F. G. S., M. R. I. A. &c. From 

 the L. &L E. &i D. Phil. Mag. for May and June, 1841. London. 

 Pamphlet, pp. 48. From the Author. 



Report of the Tenth Meeting of the British Association for the 

 Advancement of Science, held at Glasgow, in August, 1840. 8vo. 

 pp 250. Published by John Murray, London. From the Asso- 

 ciation. 



Transactions of the Royal Society of Edinburgh. Vol. 14, part 

 second ; pp. 359-754. From the Society. 



Description of a series of Geological Models ; by T. Sopwith, 

 F. G. S. Newcastle-upon-Tyne, 1841. 12mo. pp. 84. From Dr. 

 Buckland. 



