14 REPORT OF THE ACTING SECRETARY, 



Preliminary measurements testing the method employed in experi- 

 ments on the heat of vaporization and specific heat at constant pres- 

 sure of air, nitrogen, oxygen, and hydrogen have been successfully 

 conducted, and plans are making to extend the investigation to other 

 gases. 



The method employed in an investigation to determine the coeffi- 

 cient of expansion of metals and other substances at low tempera- 

 tures makes use of the interference of light, and, being of extraor- 

 dinai-y delicacy, possesses the advantage of permitting the determi- 

 nation of the expansion in detail throughout the entire range of 

 temperature, instead of giving merely the mean coefficient between 

 fixed jDoints of widely different temperatures. The results already 

 obtained in the case of gold, silver, aluminum, and glass are of an 

 interesting and unexpected character, and it is the intention to 

 extend the experiments to other substances and temperatures. A 

 set of measurements on the Hall effect in tellurium at the tem- 

 perature of liquid air has been completed during the year, and 

 preparations are already in progress for the study of the Hall 

 effect and of electric properties in general of silicon, tungsten, 

 manganese, chromium, molybdenum, and other substances which 

 have only recently become available. An extended investigation 

 on the effect of temjDerature upon the magnetic properties of cer- 

 tain steels is reported by Professor Nichols as in progress and 

 promises interesting results. 



NAPLES TABI.K. 



The applications for occupancy of the Smithsonian table at the 

 Xaj^les Zoological Station during the past year have been numerous, 

 and the appointments approved for the period from July 1, 1905, 

 (o June 30, 1906, aggregated sixteen months. Such action has 

 bL>eu made possible through the courtesy of Doctor Dohrn. the 

 director. Avho has on several occasions permitted the attendance 

 of two vSmithsonian representatives at the same time. As hereto- 

 fore, the reports submitted by various occupants of the Smithsonian 

 table mention with appreciation the excellent management of the 

 station, and the unremitting efforts of all connected with it to 

 further the work of investigators. 



Dr. Stewart Paton, formerly of the teaching staff of Johns Hop- 

 kins University, who occupied the table for six months beginr.ing 

 November 1, 1905, secured an extension of his time through June and 

 July, li!0G. His researches. relate to problems of fundamental impor- 

 tance in connection with the structure, development, and function 

 ,-•.' *-^(. nerves, and their relation to the cardiac movements. Tt is 



