24 REPORT OF NATIONAL MUSEUM, 1921. 



the library of her brother, the hite Dr. Joseph Paxson Iddings, com- 

 prising upward of 1,000 books and pamphlets, chiefly on geological 

 subjects. Doctor Iddings, as is well known, was one of America's 

 leading petrologists, and his 40 years' accumulation of author's ex- 

 cerpts in this branch of science was unusually large. 



PHOTOGRAPHIC LABORATORY. 



In illustrating Museum objects, largely for reproduction in the 

 publications and in copying plans, diagrams, etc., required in con- 

 nection with the work of the Museum, there were made in the photo- 

 graphic laboratory during the year 1,954 negatives, 11,267 black and 

 white prints, 42 bromide enlargements, 162 panoramas, and 144 lan- 

 tern slides, besides developing 467 field negatives and mounting 

 1,008 prints. A number of improvements in the apparatus and 

 equipment make it much easier to handle the work in the laboratory. 



MEETINGS AND CONGRESSES. 



As customary the National Academy of Sciences held its annual 

 meeting in the Natural History Building of the Museum on April 

 25, 26, and 27, 1921, using the auditorium for the scientific sessions, 

 open to the public, on the afternoon and evening of the 25th, and 

 on the morning and afternoon of the 26th; while the adjoining 

 committee room, No. 42-43, was used for the business meetings ex- 

 tending through the forenoon of the 27th. 



The evening session was devoted to an address by His Serene High- 

 ness Albert I, Prince of Monaco, Agassiz medalist, and was fol- 

 lowed by a reception to the Prince in the halls assigned to the Na- 

 tional Gallery of Art. Other speakers before the academy and their 

 subjects included: Gilbert N. Lewis, "Ultimate rational units"; 

 William Duane, " The quantum law and the Doppler effect " ; P. W. 

 Bridgman, " Preliminary measurements of the effect of high pres- 

 sures on the thermal conductivities of liquids"; C. E. Mendenhall 

 and Max Mason, " The stratification of suspended particles " ; J. R. 

 Carson, " Radiation from transmission lines " ; J. R. Carson and J. J. 

 Gilbert, " Transmission characteristics of the submarine cable " ; 

 W. F. Durand, "Application of the principle of similitude to the 

 hydraulic problem of the surge chamber"; E, H. Hall, (1) " Theories 

 of osmotic pressure," and (2) " Comments on the Borelius space- 

 lattice theory of the metallic state " ; G. P. Merrill, " Metamorphism 

 in meteorites"; W. M. Davis, (1) "The Island of Tagula, New 

 Guinea, its satellites and coral reefs," and (2) " The shallow seas of 

 Australasia "; A. G. Webster, (1) " On the radiation of energy from 

 coils in wireless telegraphy," (2) " On the vibration of gun barrels," 

 and (3) "On the problem of steering an automobile around a 



