





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 ; and still more difficult is it 

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

 lets, &,c, 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 unintermitling 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. 



Academic Royale de Bruxelles. Bulletin de la Seance du 6 

 Novembre, 1841. Nos. 10, 11, 12 — tome viii. Bruxelles, de 

 FAcademie. Received July 2d, 1842. 



Instructions pour l'observation des Phenomenes periodiques. 

 Extrait du tome ix, No. 1, des Bulletins de Pauteur, M. Quetelet. 

 pp. 31. 



Phenomenes periodiques du recrne vegetal. Academie Royale 

 de Bruxelles, Extrait du tome ix, No. 2, des Bulletins. 



Economie politique. Extrait de deux lettres de M. la professeur 

 Karr de Heidleberj?, au sujet de 1'application des theories mathe- 

 matiques a la solution de quelques problems d'economie politique. 



Extrait du torn, viii, No* 9, des Bulletins. 



