November 9, 191 1] 



NATURE 



43 



THE SOLAR PHYSICS OBSERVATORY. 

 T N last week's Nature we gave the terms of refer- 

 ■•'■ ence of the departmental committee appointed to 

 •consider alternative schemes for transferring Ithis 

 observatory to Fosterdown (Caterham) or to Cam- 

 bridge. 



We are informed that the Treasury has forwarded 

 -the report of the committee on this subject to Cam- 

 bridge, and that it is being considered there; so far 

 we believe no communication has been made to the 

 Solar Physics Committee, the body appointed more 

 than twenty years ago to advise the Government in 

 ■:uch matters. 



We may summarise now the action taken by the 

 ■<:ommittee and the Board of Education as already 

 recorded in Nature during the last five years. 



(i) In 1906 the Board informed 

 ihe committee that the land on 

 wJiich the Observatory is situate was 

 required for the Science Museum, 

 and requested them to make in- 

 •quiries regarding a new site. 



(2) The committee formulated the 

 conditions to be fulfilled, and, after 

 inspection of all available Govern- 

 ■ment land in iqoy, fixed upon 

 Fosterdown as fully satisfying all 

 ihe conditions. 



(3) The Treasury, in full know- 

 ledge of this, proposed Cambridge 

 as an alternative site, although it 

 fulfilled none of the required con- 

 •ditions. 



(4) The committee pointed out 

 that this raised questions concerning 

 administration, &c., and asked for 

 ■more information, and suggested a 

 committee to obtain it, consisting 

 of representatives of the Treasury, 

 the Board of Education, the Solar 

 Physics Observatory, and the 

 Meteorological Oflfice, to consider 

 fully the question of the alternative 

 sites in all its bearing. 



(5) Without any communication 

 with the committee, the Treasury 

 requested the War Office to sell the 

 Fosterdown site. 



(6) As a result of a memorial to 

 the Prime Minister this proceeding 

 was at once stopped. 



(7) The Treasury, thus compelled 

 to hold an inquiry, instead of such 

 a body as that suggested by the 

 committee, with knowledge of the 

 work done in the Solar Physics 

 Observatory and the questions of ad- 

 ministration involved, appointed a 

 committee consisting of three fellows of a Cambridge 

 college and the holder of an honorary degree of the 

 Univorsitv. 



(8) The majority of this committee has selected 

 ^'ambridge as the future site for the observatory. 



The Sites Contrasted. 



Up to the present time the actual conditions of the 

 two sites as observing stations have not been pub- 

 lished, so some trouble has been taken to prepare 

 maps to indicate their relative efficiency. 



To illustrate this the accompanying two charts are 

 here reproduced, the first (Fig. i) representing the 

 Cambridge site and its neighbourhood, and the second 

 (Fig. 2) that at Fosterdown. A study of these two 

 charts will at once demonstrate the respective values 

 NO. 2193, VOL. 88] 



of the positions for an observatory to be erected for 

 all time. 



It is well recognised that the best observations of 

 the sun are made soon after the sun has risen, so 

 that it is essential that the eastern horizon as seen 

 from the observatory should be open and free from 

 a smoky atmosphere. In the plans, lines showing 

 the directions of the sun at sunrise at both the summer 

 and winter solstices have been indicated in order to 

 point out the kind of country (town or fields) over 

 which these observations in the east should be made. 



The following comparisons show how the conditions 

 laid down by the Solar Physics Committee are ful- 

 filled or the reverse by the two sites in question : — 



■'The observatory should be at an elevation of not 

 less than 250 feet, if practicable." 



Fjg. I. — Cambridge. The selected site, 70 feet above sca-lcvol, is ,a die ^cui.c of the half-mile 

 and mile circleSj and lies 45 feet above the river flats to the eastward. The lines SS and WS 

 represent the directions of sunrise at the summer and winter solstices respectively. Solar 

 observations, which have to be made soon|after sunrise, must therefore be made through smoky 

 and misty atmosphere due to the town and river valley respectively. 



Cambridge. — 75 feet, 



Fosterdown. — 800 feet. 



" In any case it should not be in a smoke area." 



Cambridge. — Near a smoke area, namely, the town 

 of Cambridge, and this lies to the east and south- 

 east of the site, and is extending westwards, i.e. in 

 the direction of the observatory. 



Fosterdown. — No smoke area. 



"It should be away from river valley mists and 

 not upon a clay soil (chalk or gravel would be quite 

 satisfactory)." 



Cambridge. — River mists and flooded areas by the 

 River Cam — to the east and south-oast of the site. 



Fosterdown.— "No river near the site. 



" In the configuration of the ground the important 

 considerations ar< th.it the site should not be exposed 



