364 



SCIENCE 



[N. S. Vol. XXXVII. No. 949 



that they get clear away from the atom, 

 in ordinary metals they have not suiSeient 

 energy to get clear, but cling to the outer 

 parts of the atom, and have to be helped 

 by the kathode rays to escape. 



I would like to direct attention to the 

 analogy between the effects just described 

 and an everyday experience with discharge 

 tubes — I mean the difficulty of getting 

 these tubes free from hydrogen when the 

 test is made by a sensitive method like that 

 of the positive rays. Though you may heat 

 the glass of the tube to melting point, may 

 dry the gases by liquid air or cooled char- 

 coal, and free the gases you let into the 

 tube as carefully as you will from hydro- 

 gen, you will still get the hydrogen lines 

 by the positive-ray method, even when the 

 bulb has been running several hours a day 

 for nearly a year. The only exception is 

 when oxygen is kept continuously running 

 through the tube, and this, I think, is due, 

 not to lack of liberation of hydrogen, but 

 to the oxygen combining with the small 

 quantity of hydrogen liberated, just as it 

 combines with the mercury vapor and 

 causes the disappearance of the mercury 

 lines. I think this production of hydrogen 

 in the tube is quite analogous to the pro- 

 duction of X3, of helium, and of neon. I 

 have been greatly assisted in the experi- 

 ments I have described by Mr. F. W. Aston, 

 Trinity College, and Mr. E. Everett. 



J. J. Thomson 



February 8 



THE SMITHSONIAN AFRICAN 

 EXPEDITION 



The collections made by the Smithsonian 

 African Expedition under the leadership of 

 Col. Theodore Roosevelt, when received, were 

 distributed to the various departments of the 

 National Museum to which they pertained ; the 

 birds were sent to the bird department, the 

 large animals to the mammal department, the 

 plants to the botanical department, and so on. 



A number of groups of the large mammals 

 have been prepared, and a number of individ- 

 ual specimens mounted for exhibition pur- 

 poses. Most of the specimens have been 

 placed in the study series, and the duplicates 

 will be distributed by exchange or otherwise. 



The groups of large mammals now mounted 

 will shortly be placed on exhibition in the new 

 Museum mammal hall where the larger ani- 

 mals will be exhibited. Those that were on ex- 

 hibition have been temporarily withdrawn, in 

 order to place them in their proper place in 

 the classification in the hall, which is closed 

 temporarily pending the arrangement of the 

 cases containing the specimens. 



It now seems an opportune time to make a 

 final statement relating to the expedition and 

 with this in view the secretary recently com- 

 municated with the parties who contributed to 

 the fund, and has thus far received replies 

 from the following that they have no objection 

 to their names being given to the public. In 

 this connection the secretary wishes to state 

 that up to this week Colonel Roosevelt has not 

 known who the contributors were, with the ex- 

 ception of Mr. Carnegie and possibly one or 

 two personal friends. 



It has not been the custom of the institution 

 to publish the names of contributors to re- 

 search work or expeditions conducted under 

 its direction until such enterprise had been 

 completed, and only then when the contributor 

 had no objection to such publication. The con- 

 tributors include : 



Mr. Edward D. Adams, of New York City. 



Hon. Eobert Bacon, of Boston, Mass. 



Mr. Cornelius N. Bliss, of New York. 



Mr. James Campbell, of St. Louis, Mo. 



Mr. W. Bayard Cutting, of New York City. 



Mr. Andrew Carnegie, of New York City. 



Mr. Cleveland H. Dodge, of New York City. 



Mr. E. H. Gary, of New York City. 



Mr. John Hays Hammond, of Washington, D. C. 



Col. H. L. Iligginson, of Boston, Mass. 



Mr. Hennen Jennings, of Washington, X). C. 



Mr. J. S. Kennedy, of New York. 



Mr. Kalph King, of Cleveland, Ohio. 



Hon. George von L. Meyer, of Washington, D. C. 



Mr. D. O. Mills, of New York. 



