216 EIGHTH ANNUAL REPORT OF 



land. A part of the force of the particles of water forming the sinking 

 swell of the wave, in the case of an obstruction to their free descent 

 by a diminished depth, is expended in producing a cun-ent along the 

 inclined plane of the surfiice leading to the shore. 



Lieutenant Davis has entered with much ardor upon this new field 

 of research, and after an examination of various parts of the shore of 

 the United States, through a series of years, in which he was engaged 

 on the Coast Survey, has succeeded in developing the laws of action 

 which give rise to the changes before mentioned. 



He finds that the tendency of the flood-tide is to transport the matter 

 from the bottom of the ocean and deposit it on land. He is enabled to 

 explain the character of the alluvial fijrmations, to account for their 

 peculiar shape, their comparative sizes, their accumulation, and to pre- 

 dict the results of certain combinations of circumstances on their future 

 changes. The particular object of this memoir is to inquire into the 

 mechanical operations of the tides, and the uses they may have served 

 in the general economy of the globe in arranging the loose materials of 

 the earth's crust. 



Smithsonian Reports and other jnihlicutions. 



Since the last meeting of the Board of Regents, the report of Profes- 

 sor Jewett on the Public Libraries of the United Slates has been pub- 

 lished and widely distributed. It is impossible to collect at once full 

 and reliable accounts of all the libraries of the country, and this report 

 is intended merely as a beginning, to be followed by others on the same 

 subject. It has been sent to all the libraries of the United States, with 

 the request that its deficiencies may be pointed out and additional ma- 

 terials famished to render it more perfect. The great interest which is] 

 felt in this work is manifested by the amount of statistical information | 

 which has already been received in return for this volume. 



A report has also been published on the Recent Improvements in the 

 Chemical Arts. It is compiled from articles which have appeared dur- 

 ing the last ten years in the various journals of science and the arts in 

 the Enghsh, French, and German languages. Though this report is 

 chiefly intended to benefit the practical man, yet it will be found inter- 

 esting to the general reader, as exhibiting the contemporaneous advance 

 of science and art, and the dependence of the latter on the former for 

 the improvement of its most important processes. 



The accounts given in the report alluded to do not consist of des- 

 criptions of methods which have been merely proposed and published 

 without practical verification. On the contrary, care has been taken 

 to select such as have been actually tried, or such as offer great proba- 

 bility of success from the well established principles on which they 

 are based. 



The preparation of this report was entrusted to Professor James C. 

 Booth, assayer of the United States INIint at Philadelphia, who asso- 

 ciated with himself Mr. Campbell Morfit, of Baltimore. The work 

 iias been executed in a manner highty creditable to the authors, and 

 will, I doubt not, prove very acceptable to the public. Notes will be 

 aiade of the new inventions of the same class, as they appear in the 



