SCIENTIFIC SUMMARY. 
361 
lie is of opinion that these photographs show the hands in the spectrum, 
which are regarded by Profs. Dewar and Layering as proving the presence of 
nitrogen as well as of carbon. In this case, all these elements, hydrogen, 
nitrogen, and carbon, may be present in different combinations, such as 
cyanogen, or prussic acid, in the tail of the comet. If this view be really 
true, it might lend a terrible significance to comets, and the passage of the 
Earth through the tail of a comet might have the most frighful consequences 
to us terrestrial inhabitants. 
The nucleus of the comet passed quite close to two stars of tolerable 
brightness, one on June 29th, when the nucleus passed within 18" of the 
star Radcliffe 1661, and on July 13th, within 32" of the sixth-magnitude star, 
56 Tauri. The intensity of the light of this last star was considerably 
greater than that of the nucleus of the comet, though, from its superior size, 
the comet was much brighter to the unassisted eye. This comet continued 
to be visible until September. 
Comet c , 1881. — This comet was discovered by Mr. Schaberle, and 
gradually became bright, until it was nearly as bright as the preceding comet; 
indeed, the light of the nucleus seems to have been brighter, but the tail was 
not so distinct. On August 10th it approached very close to the third- 
magnitude star 9 Ur see Maj oris, and to the naked eye the nucleus of the 
comet seemed as bright as the star, whilst the tail had a length of nearly 10°. 
The comet has now swept into a favourable position for observation in the 
Southern Hemisphere. It appears to be moving in a very similar orbit to that 
of a preceding comet. 
Rncke’s Comet. Comet d, 1881. — This periodical comet has again been 
observed on its return, it having been discovered on August 25th, by Dr. 
Hartwig at Strasburg, and Herr Block at Pulkowa ; and on August 27th, 
by Mr. Common at Ealing. It is a faint, nebulous object, about 2' in dia- 
meter, and quite close to its predicted place. Towards the end of October 
it will probably be just visible to the naked eye. 
Cape Catalogue of Stars. — Mr. Stone, late Her Majesty’s Astronomer at 
the Cape of Good Hope, has just completed his great Catalogue of Southern 
Stars, the result of his ten years’ labour at the Cape of Good Hope. It forms 
a goodly volume and a valuable contribution to this branch of Astronomy. 
It is understood that it is to be supplemented by a determination of the 
proper motion of the principal Southern stars. 
Resignation of Sir G. Airy, K.C.B. — The most important event in the 
astronomical world has been the resignation of the Astronomer Royal, Sir 
George Biddell Airy, K.C.B., F.R.S., his resignation taking effect on August 
1st, or nearly on the completion of his forty-sixth year of labour, he having 
been appointed on October 2nd, 1835. Sir G. Airy will thus have held 
office for a longer period than any of his predecessors, though only for a few 
months longer than both Maskelyne and Flamsteed. Sir G. Airy, who came 
to Greenwich with a distinguished reputation, owing to his numerous brilliant 
investigations whilst holding the appointment of Director of the Observatory 
at Cambridge, has not disappointed the expectations which were aroused on 
his appointment, and during the entire period it has been under his control 
the Boyal Observatory has deservedly ranked at the head of the existing 
Meridional Observatories. It is almost impossible to over-estimate the value 
