146 CARNEGIE INSTITUTION 



\_Froni Professor E. F. Nichols, Director of the Physical Laboratory , 

 Dartnicnith College, Hanover, N. H.~\ 



February 12, 1903. 



Your letter of January 28, concerning plans and projected work 

 for a new national observatory, has been received. The plans for 

 work embodied under the three heads in the letter seem to me ad- 

 mirable, and to include work of the most valuable kind yet to be 

 done in astrophysics. My own work in astrophysics has been very 

 limited, as you know, but the outlook and far reaching extent of the 

 projected work for the new observatory seems to me in its variety to 

 include nearly everything at present worth doing. 



In particular the conditions required for the most successful meas- 

 urement of the heat radiation of the brighter stars would be a clear 

 and quiet atmosphere for night work, and a large concave mirror of 

 at least 5 feet aperture. The mirror must be so mounted that the 

 beam from the mirror will be reflected in a fixed direction, so that 

 the heat measuring instrument need not be moved in following the 

 star. It is further vers- desirable, if not absolutely necessar}', that 

 the radiometer or other heat measuring instrument may be sur- 

 rounded by constant temperature conditions during obser^-ations. 

 The results which might be expected from such an equipment I have 

 alread}^ discussed in my paper in the Astrophysical Jour?ial, vol. 13, 

 p. 138. 



I shall be only too glad to do anything I can to further the plans 

 of your committee, and only wish that any suggestions that I might 

 make could be based on a broader experience in practical astro- 

 physical work. If at any time I can be of use to your committee in 

 any waj', I hope you will have no hesitation in calling upon me. 



\Fro7n Sir William Huggins, Tulse Hill Observatory , London^ 



February 17, 1903. 



I am v^ry glad to hear that there is some prospect of establishing 

 new obser\^atories to provide for observations and researches which 

 require special conditions of position or of equipment. 



The lines of work sketched out in your letter appear to me to be 

 admirably thought out, and indeed so complete from the point of view 

 of the investigations which have the more immediate claims that I 

 do not see that there remains much, or indeed anything, for me to 

 suggest. 



