REPORT OF THE PRESIDENT, I908. 3 1 



had to be made in the laboratory under the immediate supervision of the 

 Director and his staff. 



Attention is invited to a full description of the Laboratory and its appli- 

 ances given by the Director in his report in this volume, pages 158-162; and 

 it may be remarked that a visit to this establishment will well repay one who 

 is interested in the ways and means there provided for the observation and 

 measurement of the chemical, physical, and physiological factors of human 

 and animal nutrition. 



It may suffice here to state that the laboratory is thoroly fire-proof, ex- 

 ceptionally well furnished and equipped, and is now ready to begin the work 

 for which it was specially designed. The items of cost for site and build- 

 ing; for heating, lighting, cooling, ventilating and other apparatus (involving 

 an aggregate of about 4 miles of tubing), and for furniture are given in the 

 table on page 23. 



A fact of interest and importance developed in the equipment of this 

 laboratory, and borne out by experience with other laboratories as well, is 

 that it proved highly economical to install the machinery essential to con- 

 struct special apparatus rather than to have it made by contract. The 

 advantage has proved to be much greater than that measured by the cost 

 of the machinery, which remains available for further use. 



Work of construction and investigation at the Mount Wilson Solar Ob- 

 servatory has been carried forward with a degree of energy and success 

 commensurate with the large investment required by this 



The Solar fomiidable enterprise. During the year all parts of the 



Oeservatory. ^., „ . .,, 1 1 ri 



60-nich reflectmg, equatorial telescope have been safely 



transported to the site of the Observatory, the steel dome and building for 



its reception have been completed, and the instrument is now mounted and 



substantially ready for use. A spectroscopic laboratory has been erected and 



equipped at Pasadena and a grinding machine for surfacing the mirror of 



the 100-inch Hooker telescope has been completed. 



The tower telescope described in the Year Book of 1907 has proved to be 

 a most effective instrument in solar research and has led to discoveries with 

 regard to sun-spots of as great importance, probably, to terrestrial and molec- 

 ular physics as to solar physics. For an account of these discoveries the 

 reader must be referred to the report of Professor Hale in this volume, pages 

 146-157, and to the accounts and discussions in current journals, since any 

 attempt at explanation in semi-popular language is liable to be premature, if 

 not misleading at the present writing. It may be confidently anticipated, how- 

 ever, that the progress thus inaugurated will lead rapidly to still more im- 

 portant results than those already establisiied. 



In the meantime many other lines of investigation are proceeding simul- 

 taneously toward an elucidation of the phenomena presented by the sun and 

 similar stars. By aid of the Snow (horizontal) telescope, the tower telescope. 



