Janssen Solar Photograph and Optical Studies, 297 
Art. XLV.—On the Janssen Solar Photograph and Optical 
Studies ; by S. P. LANGLEY. 
Mr. JANSSEN, in papers lately presented to the French Insti- 
tute* has given an account of recent results in solar-photo- 
graphy, obtained by him at the observatory of Meudon, and 
from the comments of Messrs. Huggins, Lockyer, De la Rue 
and other competent judges, it has been understood that 
remarkable advances have been made over any before pro- 
duced. A copy has been published in the Annuaire du 
or rice-grain-” like forms as had been commonly sup- 
posed. The term “rice-grain,” it was carefully explained, was 
Incorrect, and as an illustration imperfect. 
* Comptes Rendus, Oct. 29th and Dec. 31st, 1877. 
