I860.] Physics. 319 



the formation of a number of separate bodies, such as exist in our sun 

 and in the stars ; and such an advance in the process of formation 

 into stars would have been indicated by a more complex spectrum. 



It is a point of some interest at present to know whether certain 

 lines in the solar spectrum are due to the sun or to the earth — that is, 

 whether they are due to the absorption of rays by the solar or the 

 terrestrial atmosphere. Knowing this, we should be enabled to ascer- 

 tain whether special bands which are seen in the spectra of the 

 planets, Jupiter especially, were due to their atmospheres. Father 

 Secchi* has lately communicated the results of some very accurate 

 measurements which he has made upon these bands with the object of 

 learning to what they were due. The solar rays and that of sodium 

 served as the starting-point for the measurements. The atmospheric 

 rays were determined by observing the air near the horizon. The 

 moon was also sometimes made use of when it was a little above the 

 horizon. Great care was taken each time to fix the micrometric slit 

 upon one of the strongest atmospheric rays, to see if they coincided 

 or not with those of Jupiter. In the interval between the observa- 

 tions the instrument was left untouched, although it was subsequently 

 observed that this precaution was superfluous. The various bands 

 were not equally easy to measure, for some are more diffused on one 

 side than the other ; and that of the dark red is difficult, espe- 

 cially if the air is at all impure. The results show that the bands of 

 Jupiter do not agree at all with those of our atmosphere, whilst some 

 are quite wanting. The general results do not disprove the existence 

 of solar rays in the planet, but show that its atmosphere has a strong 

 absorbing power, and a different one from ours. 



At the meeting of the Manchester Literary and Philosophical 

 Society, on January 10, Dr. Eoscoe exhibited some very interesting 

 photographs of the fixed lines in the solar spectrum made by Mr. 

 Rutherford, of New York. These photographs exhibit groups of 

 thousands of lines, extending from near the line b in the green, to 

 beyond H in the violet, and serve as a most valuable confirmation of 

 the accuracy of Kirchhoff s maps. Each line in these maps can be 

 easily and distinctly traced in the photograph, whilst many bands 

 drawn as single ones by Kirchhoff are seen in the magnified photograph 

 to consist of bundles of fine lines. These photographs were prepared 

 with three 60° bisulphide of carbon prisms. 



A new spectroscope, in which the great desideratum of direct 

 vision is obtained, has lately been made by the well-known optician, 

 Browning, from designs furnished him by A. Herschel, Esq. The 

 principle is as follows : — What is called a 3 to 1 right-angled prism, 

 in which the hypotenuse is three times as long as the base, is placed 

 in the path of a ray of light in such a manner that the ray falling at an 

 angle of 45° on the shortest side of the prism, is refracted, then twice 

 reflected totally, when it emerges at an angle of 45° from the prism, 

 but in the same direction as when it entered. The light is dispersed 

 both at its entrance and at its emergence ; but owing to the two reflec- 



* ' Phil. Mag.,' vol. xxviii. p 486. 



