20 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1918. 



There is now in the park a total of 1,247 animals, representing 345 

 distinct species. These include 483 mammals, 706 birds, and 58 

 reptiles. The several species are enumerated in detail in the superin- 

 tendent's report in the appendix. 



A most interesting recent accession is the first specimen of the 

 glacier bear or blue bear ever known to have been captured alive. 

 It has a very limited distribution in the region of the St. Elias 

 Alps, near Yakutat Bay, Alaska. Being one of the rarest and least 

 known of the great game animals of America, specimens have been 

 eagerly sought for zoological gardens. Among other accessions may 

 be noted keas, or sheep-killing parrots, and some flightless rails from 

 New Zealand, and a large boa constrictor, 11 feet long, from Trinidad. 



For several years I have urged the purchase of certain parcels of 

 land along the western boundary of the park and in 1913 an appro- 

 priation was made by Congress for that purpose, but as the purchase 

 could not be completed before the time limit of the appropriation, 

 further legislation becomes necessary for renewal of the allotment. 



The superintendent calls attention to a number of important needs, 

 including roads, bridle paths, automobile parking space, grading and 

 filling, a new aviary building, a reptile house, and outdoor quarters 

 for mammals. 



A striking mark of the appreciation and interest of the children of 

 Washington in the National Zoological Park is the tablet placed in 

 the elephant house to the memory of the elephant " Dunk," through 

 subscription to a popular fund by the children of Washington, 

 " whose favorite Dunk was for more than a quarter of a century." 



ASTROPHYSICAL OBSERVATORY. 



The general direction of the work of the Observatory has continued 

 under Dr. C. G. Abbot, who, in addition to these duties, has been 

 occupied during the year with a number of scientific investigations 

 directly connected with the war. 



The investigation of the absorption of long-wave rays by long 

 columns of air containing known quantities of water vapor, refer- 

 ence to which was made in my last report, have been continued and 

 the results to date published in the Smithsonian Miscellaneous 

 Collections. In describing his work Mr. Fowle says : 



The main purpose of this research was to determine the transparency of 

 water vapor, under atmospheric conditions, to radiation such as the warm 

 earth sends toward space. Upon the absorptive property of water vapor rests 

 in part the virtue of the atmosphere as a conservator of the heat which 

 the earth receives from the sun. Radiation from the sun reaches the earth's 

 surface diminished by a certain portion scattered toward space and certain 

 other portions absorbed in the gases and vapors of the atmosphere. The re- 

 turn of the energy of this radiation back to space is an indirect process. The 



