REPORT OF THE SECRETARY. a5 
- Smithsonian books constantly used by the bureaus, of which several 
thousand are now scattered through various rooms in the Smith- 
sonian Building. 
LANGLEY MEMORIAL TABLET. 
The memorial tablet authorized by the Regents to be erected in 
the Smithsonian building commemorative of the aeronautical work 
of the late Secretary Langley has not yet been completed. <A design 
for the tablet has, however, been prepared and is under consideration 
by the committee appointed for the purpose. 
INTERNATIONAL CONGRESSES AND CELEBRATIONS. 
The Institution each year receives invitations to numerous scien- 
tific congresses and celebrations in the United States and abroad, 
but as funds are not available for the expenses of delegates few of 
these invitations can be accepted. In some instances, however, it is 
possible to arrange for representation by collaborators of the Insti- 
tution who are visiting the localities on official or private business. 
Congress of Americanists—Dr. AleS Hrdli¢ka was appointed rep- 
resentative of the Smithsonian Institution and the National Mu- 
seum and delegate on the part of the United States at the second 
session of the Seventeenth International Congress of Americanists, 
held in the Museo Nacional, Mexico City, September 8 to 14, 1910. 
He presented an account of his recent explorations in Peru, and also 
described the uncovering of an especially interesting sepulchre which 
he had been invited by the Mexican authorities to open in the ancient 
ruins of San Juan Teotihuacan. 
The meeting was held in the Museo Nacional, and was well at- 
tended, especially by scientific men from the United States. 
Dr. C. W. Currier, of Washington, was also designated delegate 
of the United States and a representative of the Smithsonian Insti- 
tution at the above congress. 
International American Scientific Congress—Mr. Bailey Willis, as 
delegate on the part of the Smithsonian Institution, attended the 
International Scientific Congress which was held at Buenos Aires, 
Argentina, July 10 to July 25, 1910. 
Geological Congress —In August, 1910, the Eleventh International 
Geological Congress met in Stockholm. Dr. George F. Becker, of 
the United States Geological Survey, was:a delegate on the part of 
the Smithsonian Institution. The congress was more largely at- 
tended than any of its predecessors, and nothing could exceed the 
hospitality of its reception. The principal subjects of discussion 
were the distribution and extent of the iron ore deposits of the 
world, Cambrian paleontology, and the change of climate since the 
last maximum of glaciation. To all of these subjects painstaking 
