66 REPORT OF THE SECRETARY. 



(12) A new prism holder, with large glass flat, from J. A. Braskear. 

 II. Accessory apparatus : 



(1) A complete instrument-maker's lathe, with outfit of tools and ckucks. 



(2) A 30-inck kand and power planer for metal work, with ckuck, etc., from 



tke Hendley Mackine Company. 



(3) A 40-ligkt incandescent dynamo, witk rkeostats, etc., from Westing- 



kouse Electric Company. 



(4) A one-kalf korse power motor, from Akron Electric Company. 



(5) A one-fourtk korse-power water motor and Sturtevant pressure fan, witk 



accessory apparatus for cooling tke air of tke Observatory. 

 The total value of the apparatus purchased during the year was about $3,000. 



MINOR WORK OF THE YEAR. 



In addition to Mr. Wadswortk's work with Prof. Michelson in the establishment 

 of the length of the standard meter in terms of the wave length of light, at the 

 International Bureau of Weights and Measures, reference to which has already been 

 made, the following special work, wkick kas been done during tke year, may be 

 mentioned: 



(1) Tke preparation of a complete series of line-skaded drawings of tke principal 

 pieces of apparatus in tke observatory on a scale requisite to skow their detailed 

 construction. 



(2) The preparation of a series of enlargements of moon photographs from the 

 Kenwood and Lick observatories, photographs. 



(3) Experiments in temperature and radiation work. 



During tke latter part of tke year preliminary experiments were begun and carried 

 on at intervals looking to tke systematic preparation for another extended research, 

 which I have proposed to soon begin to determine the physical relation between 

 temperature and radiation. The experiments have mostly been directed to the 

 establishment of a satisfactory source of temperature and means of measuring the 

 same. The various apparatus, etc., for the prosecution of this work at an early date 

 kas either been ordered or already installed. 



(4) Some further attempts have been made at solar pkotograpky, but, as the 

 experience of last year conclusively skowed, tke atmospheric conditions kere in tke 

 city are very unfavorable to any satisfactory Avork in this direction. 



PERSONNEL. 



The force of the Observatory consists of a Senior assistant, and an instrument- 

 maker, and an assistant instrument-maker. During tke past year tke Observatory 

 has also bad at different times special assistants, among wkom I wisk to acknowl- 

 edge tke assistance of Mr. J. G. Hubbard, to wkose pkotograpkic skill several 

 improvements of this part of the work are due. 



