Lieut. J. M. GILLIS, of our navy, and the Observatory at George- 

 town College, assigned to the care of the Rev. JAMES CURLEY. 

 Until then, I remain yours, respectfully, 



J. C. B. 



LETTER No. XII. 



INTERNATIONAL AND DOMESTIC EXCHANGES; DEPOT OF CHARTS 

 AND INSTRUMENTS, AND GEORGETOWN COLLEGE OBSERVATORY. 



WASHINGTON, March 9, 1844. 



GENTLEMEN : Having committed the oversight in my last of over- 

 looking a very interesting report by Mr. MARKOE, of a Committee 

 on Exchanges, to the National Institute, consisting of Col. AEERT, 

 Mr. MARKOE, Mr. DAYTON, and Dr. KING, on the 13th December, 

 1841, and which has received the sanction of that body, (see 2d 

 Bulletin, pp. 162, and 164,) before proceeding to the immediate 

 topics of this number, I take the occasion of referring my readers 

 to that paper as one well worthy a perusal. 



The committee recommend : 1st. That a system of exchanges 

 be entered upon without delay. 2d. That the curator and assist- 

 ants be directed, for this purpose, to separate all duplicates, except 

 those from the Exploring Expedition ; and that they select and 

 label such specimens as are to be sent to individuals or societies. 

 3d. That the first step taken be to discharge the obligations of ex- 

 change already incurred by the Institution. 4th. That a commit- 

 tee be appointed, to whom the curator shall submit all sets of 

 specimens thus set aside for any given exchanges, who shall decide 

 upon the equivalency before said specimens shall be boxed up and 

 sent off. 5th. That in all cases of difficulty which may arise, ref- 

 erence must be made to the President or Vice President of the In- 

 stitution for decision, who will, if they conceive it necessary, sub- 

 mit the question to the Institution. 6th. That a book be kept by 

 the curator, subject at all times to the inspection of the committee, 

 in which must be noted the contents of each box or package, lists 

 of the articles for which they are the equivalents, the name and 

 place of the society or individual to whom one set is to be sent and 

 from whom the other has been received. 



The support, co-operation, and patronage of the public are all 

 that is wanting to enable the Institute to carry a proper plan of In- 



