Progress of Astronomy during the Year 1879. 449 
they occur at Kew, and at Kew one day before they occur at 
Utrecht. The declination ranges at Kew and Prague exhibit 
certain common periods, which may be regarded as the same, or 
very nearly the same, as the above-mentioned meteorological 
periods, the similar magnetic phase appearing to occur at Kew 
about one day before they occur at Prague. Sun-spot records from 
1857-68 appear to show certain solar inequalities very like the 
magnetic and meteorological inequalities in point of period. 
M. Janssen continues his photographic observations of the 
surface of the sun, and has, in the ‘‘ Annuaire du Bureau de 
Longitude” for 1879, and in the “ Report of the British Asso- 
ciation,” given an account of recent progress in solar physics, 
particularly of what he supposes to be a new discovery—the 
maximum of photographie intensity of the spectrum for iodide 
of silver near G, which by short exposures makes the spectrum 
very nearly monochromatic. As remarked in the British 
Journal of Photogravhy, No. 1009 (vol. 26), this is by no 
means a new discovery, but a fact known since the earliest days 
of photography. 
In the American Journal for July Dr. J. W. Draper has a 
paper on the distribution of intensity of light in the spectrum. 
He finds that in the diffraction spectrum the luminous intensity 
is equal in all the visible regions, all the colours being simul- 
taneously obliterated by an extinguishing light. 
5. The Moon. 
The region around Hyginus continues to draw the attention 
of lunar observers, and several papers have appeared during the 
year, among which Lord Lindsay’s and Dr. Copeland’s, in the 
Monthly Notices for January, and Mr. Pratt’s, in The Obsev- 
vatory for January, deserve special notice. On the whole it 
seems rather doubtful whether Dr. Klein’s “crater” is really a 
new formation or not, at any rate its visibility depends so very 
much on the altitude of the sun, that it is quite possible that 
the earlier observers may have overlooked it. The discussion on 
this subject at the January meeting of the R. A.S. does not throw 
much light on it.* 
* Obs. ii., p. 327-31. 
ScrIEN. Proc., R.D.S. Vou. 11, Pr. vi. 
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