SCIENTIFIC SUMMARY. 
311 
Supposed Nezv Spot on the Moon. — The u Cologne Gazette ” announces 
that Herr Herman J. Klein has discovered a large lunar crater of recent 
formation. It is situated in the large plain lying to the west of Hyginus. 
It presents at the time of the first quarter the appearance of a vast cavity 
filled with shadow, and having a diameter of about 4,400 yards. The dis- 
covery, or rather the existence of this cavity, has been confirmed by Schmidt, 
of Athens, and others ; whether it really is a new formation remains to be 
seen. Nothing is shown in this space in Mr. Madler’s large map, but in 
Rutherford’s “ Photographs of the Moon ” at and near the time of the first 
quarter, the plain is by no means so level as it might be inferred to be from 
Madler’s chart. 
Photography at the least refrangible end of the Solar Spectrum. — Captain 
Abney read a preliminary paper before the Astronomical Society two years 
ago, upon the possibility of photographing the red end of the spectrum. He 
has now made considerable progress in his researches, and has laid the re- 
sults before the Astronomical Society. The first photograph was one taken 
through three prisms of dense flint glass, placed at the angle of minimum 
deviation for B. The focal lengths of the collimator and camera were 18 
inches and 2 feet respectively, and a condensing lens of 6 feet focus was 
employed to collect the light, the middle of the collimating lens alone being 
filled with solar rays. In front of the slit was placed a plate of orange 
glass to cut off the suffused blue rays, which experience had shown to be 
inimical to the production of good negatives, owing to the light dispersed in 
the prisms themselves. The impressions of bands in the ultra red are found 
an enormous distance below A. Roughly speaking, A corresponds to 
wave-lengths of 7,600 tenth-metres, and D 5,000 tenth-metres, while the 
photographs show bands as far below A as would correspond to wave- 
lengths of 10,400 tenth-metres. But this negative, remarks Captain Abney, 
il has no practical scientific value, as the ultra red is so tremendously com- 
pressed that the absolute wave-lengths could not be obtained from it.” 
Using, however, a speculum-metal grating by Rutherford, having about 8,600 
lines to the inch, Captain Abney was able to photograph the spectrum of 
the second order. With a grating of about twice as many lines to the inch, 
another photograph was taken, of which the Astronomer Royal for Scotland 
remarks that, viewing them with high magnifying power in a compound 
microscope long since arranged for such things, the effect was astounding. 
11 1 almost thought,” he adds, u I was back again at Lisbon, viewing the sun’s 
spectrum itself as I used to see it.” This acknowledgment of the value 
of the photograph was peculiarly gratifying as coming from an astronomer 
who had paid special attention to this part of the spectrum. After describ- 
ing further operations, and the methods used, which belong rather to 
physical than astronomical or optical matters, Captain Abney remarked in 
conclusion, that he hoped in a short time to reduce the expenses con- 
siderably. 
Phenomena for the Quarter. — On July 25, at 9 a.m., Jupiter will be in 
opposition to the sun. On July 29 there will be a total eclipse of the sun 
not visible at Greenwich. On August 12 the moon will be partially 
eclipsed. The following are the epochs of the principal phenomena : — 
