12 REPORT OF THE ACTING SECRETARY. 



waters, and the material now at command will thus furnish the 

 means for an original biological investigation of much importance. 



Dr. Edward L. Greene, who, as noted in previous reports, has in 

 course of preparation a paper to be entitled " Landmarks of Botan- 

 ical History," reports satisfactory progress. The completed manu- 

 script is to be submitted early in 1907, and it is believed that the 

 intimate knowledge of the history of botany possessed by Doctor 

 Greene will render its publication of great value to students in this 

 branch of science. 



The International Fishery Congress will hold its fourth general 

 meeting in the city of Washington during the summer of 1908, and to 

 enhance the interest in its proceedings prizes for contributions of 

 merit have been offered by a number of organizations and individ- 

 uals. In view of the importance of the occasion the Institution has 

 tendered an award of $200 for the best essay or treatise on " Inter- 

 national Regulations of the Fisheries on the High Seas, their His- 

 tory, Objects, and Eesults." 



HODGKINS FUND. 



Several important investigations are in progress under grants 

 from the Hodgkins fund of the Institution, the results of which have 

 not yet been fully reported. The conclusion of others has been un- 

 expectedly delayed, and these will properly be summarized in a later 

 report. 



In March, 1906, Dr. R. von Lendenfeld announced the conclusion 

 of the second part of the investigations on the organs of flight car- 

 ried on under his direction. It relates to the air sacs of birds, and 

 was conducted by Mr. Bruno Miiller, whose report has been submitted 

 and approved for publication by the Institution. 



Another paper, on the wings of hymenopterous insects, prepared 

 imder the same supervision by Dr. Leo Walter, has also been received. 



The investigation of Prof. W. P. Bradley, of Wesleyan University, 

 to determine the relation between the initial and the final tempera- 

 ture of air which in flowing through a nozzle passes from a high 

 pressure to a lower is reported as progressing satisfactorily. Oppos- 

 ing theories being held as to the physical principle invol\^ed in this 

 type of expansion, special interest is felt in these experiments, and 

 while they are not yet sufficiently advanced for a definite conclusion 

 to be drawn from them, the present results are such as to justify a 

 second moderate grant for their continuance during the coming year. 

 It may be added that this investigation is expected to form an 

 important part of an extended inquiry into the factors which make 

 for efficiency in an air liquefier. 



