10 REPOET OP THE SECRETARY. 



research will remain the property of the Institution. Prof. E. C. 

 Pickering, of Harvard University Observatory, while unable to give 

 his personal attention to the details of the investigation, furthered its 

 inception by valuable suggestions as to the electrical part of the 

 experiments. 



The meteorological experiments at Blue Hill, just alluded to, and 

 which are circumstantially described In* Mr. Rotch, the director, in 

 his printed bulletins, have been steadily progressing, aided, as before 

 stated, ))y a Hodgkins grant. 



On Februarv 1'2, 1899, one of the automatic kites sent up from the 

 station reached the height of 12,507 feet, or nearly 2i miles, making 

 the highest ascension on record. As a proof that the increased height 

 of this flight is due to improved apparatus and methods, rather than to 

 some fortunate combination of air currents at the time, it may be added 

 that the average height of five flights made at Blue Hill l)etween Feb- 

 ruary 23 and 28 of the same j'ear was aljout 10,280 feet, this average 

 being only 806 feet less than the highest single flight ever attained 

 previous to that of Fel)ruary 12, 1899. 



It has been found at the Blue Hill Observatorj^ that the exposure of 

 the instruments carried by kites is probably equal to that of instru- 

 ments at the ground, and the results have so far proved more satis- 

 factory than those recorded by instruments carried by balloons. 1'he 

 stationary position of the kites, as opposed to the motion of free bal- 

 loons with the atmospheric currents, also renders possible a record of 

 the progressive changes of the atmosphere, as well as a comparison of 

 similar coincident phenomena at a fixed point on the surface of the 

 earth. Kites can, moreover, reach higher altitudes than captive bal- 

 loons have yet attained, and are better fitted to withstand the wind 

 velocities to be encountered at great heights. Experiments are still 

 in progress, and it is hoped that a union of the two methods of explor- 

 ing the atmosphere — by means of kites and b}" captive balloons — ma}'^ 

 eventually give better results than any yet attained b}^ either method 

 alone. 



It maj" be noted that Mr. William A, Eddy, who experimented, by 

 the aid of a small grant from the Hodgkins fund, in 1894 at Bayonne, 

 New Jersey, was the first to demonstrate the adaptability of a modern 

 kite of his own device to the purposes of scientific experiment. 



The investigation on the intensitj'^ of sound, conducted by Prof. 

 A. G. Webster, of Clark University, Worcester, Mass., is reported 

 as making satisfactory progress. It is expected that by means of the 

 new instrument designed b}" Professor Webster an absolute measure 

 of the intensity of a sound, even when rapidly varying, will be 

 recorded with an accuracy not hitherto attained. 



Extended researches upon the propagation, reflection, and diffrac- 

 tion of sound are in progress, and results of much practical value are 



