REPOET OF THE SECEETAEY. 41 



<30X)81 books and 95,594 pamphlets. Typewritten lists of original 

 articles appearing in scientific periodicals reaching the Institution 

 for the Smithsonian deposit at the Librar^^ of Congress have been 

 circulated among the head curators of the Museum for their informa- 

 tion and dissemination among the staff generally. There is a demand 

 from other Government departments and research organizations for 

 copies of these lists which the Museum is unable to supply, through 

 lack of mechanical equipment and assistants. 



The number of visitors to the Natural History Building was 

 441,604; to the Arts and Industries Building, 262,151; to the Smith- 

 sonian Building, 83,384; and to the Aircraft Building, 46,380. All 

 the Museum exhibition halls are open free to the public every week- 

 day in the year. In addition those in the Natural History Building 

 are open every Sunday afternoon, and this year those in the Smith- 

 sonian Building were open on Sunday afternoons in April. All the 

 Museum offices and exhibition halls were closed, however, on Novem- 

 ber 11, 1921, on account of the burial of America's unknown soldier. 



Eespectfully submitted. 



W. DE C. RaVENEL, 



Administrative Assistant to the Secretary^ in charge 



United States N actional Museum,. 

 Dr. Charles D. Walcott, 



Secretary^ Smithsonian Institution. 



