396 SCIENTIFIC RECOED FOE 1885. 



and to a considerable extent prepared for printing. It is expected that 

 they will form Part iii of the Transit of Venus Eeports. ISTo progress 

 has been made in the reduction of the photographs during the current 

 year, and it is not proposed to take them up again until after all the 

 manuscript relating to time, latitude, and longitude has been prepared 

 for the printer. 



The work of printing Part ii of the Transit of Venus Eeports has re- 

 cently been resumed, and will probably be completed at an early date. 

 This part will form a volume of about five hundred quarto pages, and 

 will contain the records of all observations made at the United States 

 stations for observing the transit of 1874, together with the correspond- 

 ing reductions and discussions, excepting only those relating to the 

 photographs. 



The French photographs of the transit of Venus.— The measurement 

 of the seven hundred photographs obtained at the various French sta- 

 tions during the transit of Venus, 1882, is about to be commenced. An 

 office has been organized for the purpose, the necessary credit has been 

 granted, and a measuring instrument belonging to the Meudon Obser- 

 vatory and lent by M. Janssen, has been supplied. This will be replaced 

 in January, 1886, by a smaller one by the same makers, MM. Brunner 

 Fr^res. The measurements, it is expected, will be completed in fifteen 

 months. 



Photographic evidence as to the constitution of sun spots. — "M. Janssen, 

 remarking on some exquisite photographs of sun spots which he has ob- 

 tained during the past year, calls attention to the evidence they supply 

 as to the continuation of the granulation of the general solar surface, 

 into the spots. A photograph of the great spot of 1885, June 22, for 

 example, to which he particularly alludes, shows that the bright region 

 which surrounds the penumbraB of large spots has not a different con- 

 stitution from that of the photosphere in general, since it is made up in 

 like manner of granular elements, usually of a spherical form. The 

 marked increase in brightness of such regions the photographs show to 

 be due to the granulations being more thickly clustered, brighter in 

 themselves, and arranged on a brighter background. In the penumbra 

 the granulations are still distinguishable, but they are less luminous 

 and more scattered, leaving dark gaps between the rows of grains, the 

 familiar striated appearance of the penumbra being due to the arrange- 

 ment of the granulations in ranks and lines, like beads on a thread. 

 The grains become in general smaller and duller near the nucleus, where 

 they seem to dissolve. The same spot presented two very remarkable 

 bridges, and a very bright isolated mass of luminous matter which 

 united them. This luminous matter and the bridges were also formed 

 of granular elements resembling the others. Many other photographs 

 have revealed a similar structure in penumbrsB and their surroundings, 

 so that it is highly probable that 'the luminous matter which forms the 



