288 proceedings of the american academy 



" Third Class. — Moral and Political Sciences. 

 First Division. Moral and Intellectual Philosophy. 

 Second Division. Philology and Ethnology. 

 Third Division. Politics, Political Economy, and Jurisprudence. 

 Fourth Division. ^Esthetics." 



" Voted, That the Secretaries be authorized and directed to cause to 

 be prepared a suitable diploma or form of notification of election for 

 the Foreign Honorary Members." 



Dr. B. A. Gould, Jr. presented to the Academy, in behalf of 

 its author, a volume entitled " The Exposition of 1851, or 

 Views of the Industry, Science, and Government of England, 

 by Charles Babbage, Esq.," and called attention to a new and 

 uniform system of lighthouse signals, recommended by Mr. 

 Babbage for universal adoption. 



Tbree hundred and fifty-flfth meeting. 



January 6th, 1852, — Monthly Meeting. 



The President in the chair. 



Professor Peirce, in behalf of the committee to whom was 

 referred Lieutenant C. H. Davis's paper on the subject of the 

 deterioration of Boston harbor, read the following report : — 



" The committee to whom was referred the memoir of Lieutenant 

 C. H. Davis upon the state of Boston harbor, have examined the same, 

 and ask leave respectfully to report, that the memoir contains an 

 enumeration of several changes that appear, by a comparison of the 

 charts made at various times, and by other evidence, to have taken 

 place in some of the most important "channels of the upper harbor. 

 This part of the memoir embraces a subject entirely local in its char- 

 acter ; yet its importance, as affecting the prosperity of a great mari- 

 time city, our birthplace and home, may well compensate for the ab- 

 sence of that general interest which belongs to many other subjects of 

 our transactions. The memoir, furthermore, contains an examination 

 of the various causes by which the changes of the harbor have been 

 brought about, influenced, or modified, and by which further changes 

 may be produced. These causes are intimately connected with those 

 general hydraulic forces which are at work wherever tides and streams 



