141 
PHOTO G-RAPHICAL SECTION. 
March 12th, 1867. 
Samuel Cottam, Esq., in the Chair. 
Mr. Wardley said that he had observed recently in the 
Photographic Journals that complaints were made as to 
the appearance of streaks on collodion plates in the direction 
of the dip. He had never until lately seen anything of the 
kind, but he had been using some collodion which produced 
the markings, and he noticed that the streaks could be seen 
on the plates when taken out of the bath, and before expo- 
sure. The marks were not such as would be removed by 
re-dipping the plate and moving it from side to side in the 
solution ; and he thought the cause would be found to arise 
from the collodion being over iodized. He had used collodion 
containing about one-eighth less iodizing solution and found 
that the streaks had disappeared. 
Mr. Brothers, F.R.A.S., exhibited a number of photo- 
graphs taken during the Eclipse of the Sun on the 6th inst. 
He said that he had anticipated some difficulty in photograph- 
ing the sun from the excess of light causing over exposure, 
as the image was taken at the focus of the telescope without 
enlargement through an eyepiece. To overcome that diffi- 
culty the aperture of the telescope was reduced first to two 
inches, and then to half an inch ; and collodion and develop- 
ing solution which had been mixed upwards of twelve 
months, and . an old silver bath were used. The exposure 
was as instantaneous as could be made by hand. 
