ASTRONOMY AND METEOROLOGY. 389 



brilliancy upon our astonished sight on the last evening of June, 

 1861. The successive returns to perihelion of the comets of D' Ar- 

 rest, Brorsen, Encke, and Faye, have enabled the elements of these 

 bodies to be re-observed, and their periodicity to be observed with an 

 increased degree of accuracy. Professor Encke, in particular, has 

 discovered, in the course of his researches in relation to that called by 

 his name, additional indications of the existence of a resisting medium 

 affecting the orbital motion of the comet, and accelerating, in conse- 

 quence, its successive returns to the perihelion. This retardation he 

 has ascertained to amount, during nine revolutions of the comet, to 

 4,544 days. 



M. Dove, of Berlin, has recently addressed a paper to the Prussian 

 Academy, in which he asserts that neither the comet of 1861, nor in 

 fact any comet, ever shone with its own, but with borrowed light. 

 There would, therefore, be no longer any danger to be apprehended 

 from a too near approach of these erratic bodies to the earth ; as 

 they do not burn, they cannot ignite. 



New Star Charts. Sir Henry James, chief of the Ordnance 

 Survey of Great Britain, has prepared, and is about to publish, four 

 very useful charts of the stars, and two maps of the world, with the 

 lines of magnetic declination marked on them. The celestial charts 

 are laid down on a geometrical projection of two-thirds of the sphere ; 

 two of them present the stars of the northern hemisphere, two of 

 them those of the southern. The first map contains the European 

 circumpolar regions, and has the great continent of Africa in the 

 centre ; the second gives the southern circumpolar regions. These 

 maps represent the earth as it would appear to an observer at this 

 point of sight, and very singular the configuration of land and water 

 seems. To the scientific man these charts and maps will be of great 

 interest and value. 



Lescarbaulfs intra-Mercurial Planet. During the past year 

 (1861) a diligent and systematic "search has been made at the Cam- 

 bridge (Mass.) Observatory for the intra-mercurial planet (supposed 

 to have been seen by Dr. Lescarbault) during the period assigned by 

 mathematicians for its possible transit of the sun's disc. For these 

 observations a five-foot equatorial telescope was used, to which was 

 fitted a solar eye-piece, on the plan recommended by Sir John Her- 

 schel. The sun's image is reflected from the first surface of a glass 

 reflector, so placed that the greater part of the incident rays are 

 transmitted through the second concave surface, and are dispersed by 

 it. The intensity of the light and heat is thus considerably dimin- 

 ished, and only faintly-tinted screens are needed to protect the eye. 

 A very agreeable definition of the surface of the sun is obtained by 

 this arrangement. 



With this telescope, the surface of the sun was explored from the 

 18th of January to the 12th of April ; the search being made at inter- 

 vals of one or two hours, from 9 A. M. to 4 p. M. The search, how- 

 ever, like others instituted in various other localities, furnished no 

 testimony in confirmation of M. Lescarbault's observations. 



The great Nebula in Orion. Some interesting researches on the 

 character of the great nebula in Orion have recently been made by 

 Professor G. P Bond, of the Cambridge (Mass.) Observatory. 

 3C* 



