22 REPORT OF NATIONAL MUSEUM, 1920. 



material. In making additions to the collections 16,200 more dupli- 

 cate specimens were used, nearly 13,000 being plants; for these the 

 Museum has or will receive an equivalent. 



Material sent out to specialists for study on behalf of the Museum 

 amounted to 13,838 specimens, mainly biological. 



WAR COLLECTIONS. 



Through cooperation of the Navy and the War Departments, 

 the stream of material reaching the Museum illustrative of the 

 World War filled the quarters assigned to the division of history in 

 the Arts and Industries Building, overflowing into the Natural 

 History Building, and the Aircraft Building, the temporary metal 

 structure obtained from the War Department. 



Prior to July, 1919, very little material had been received illus- 

 trating the work of the Navy during the World War, with the 

 exception of some uniforms of the Marine Corps and the insignia 

 of its various branches. At that time it was decided to assign the 

 rotunda of the Natural History Building for this purpose, and after 

 a conference between Assistant Secretary Roosevelt and the secretary 

 and officers of the Museum, Lieutenant Commander L. P. Warren 

 was asked to take charge of this work. A number of exhibits were 

 received during the year, the most important of which are a para- 

 vane, which is a device attached to battleships for the purpose of 

 destroying mines; an anti-aircraft gun and a Y depth charge gun 

 for the destruction of submarines ; a collection of British naval air- 

 plane bombs; a large number of relics from the sunken battleship 

 Maine; a one-pound gun; a German torpedo 18 feet long; a Davis 

 gun for airplanes; and a naval range finder. 



During the month of June the large 6-inch naval gun which fired 

 America's first shot in the World War was delivered at the building. 

 Owing to its weight and the impossibility of getting, it into the 

 building it was placed on the east driveway, where it makes a most 

 impressive exhibit. 



The War Department continued its generous co-operation by con- 

 tributing material illustrating the military activities of the United 

 States, the Allies and the enemy countries in the following branches : 

 Air service, ordnance, chemical warfare, quartermaster, Engineer, 

 Medical, and Signal Corps. The material was selected especially for 

 the Museum with a view to illustrating graphically the military his- 

 tory of the war for the benefit of the public and for historical and 

 scientific research. 



From the Air Service came military airplanes showing types of 

 machines used by the United States, France, and Germany, includ- 

 ing a De Haviland 4, tractor biplane of type originally developed 



