REPORT OF THE SECRETARY. 121 



Note (added February 13, 1888).— This lust clause above cited is to be understood 

 as iucluding the books purchased at the expense of the Museum appropriation, but 

 not necessarily books obtained by exchange for Museum publications, as it would 

 be dmicult, if not impossible, always to discriminate these under our present system. 

 This point is reserved for future consideration, but i)rovisionally it is understood that 

 the librarian is to send books to the Library of Congress if not evidently meant for 

 the Museum. 



S. P. Langley, 



Secretary. 



