164 
must observe not to move the bottle during the time of the 
operation.” 
Mr. Coote exhibited some snow scenes, the negatives of 
which were taken on collodio-albumen plates. Some of 
these beautiful views were slightly defective in the high 
lights, a number of vein-like markings appearing in the sky 
and foreground. 
Mr. Wardley stated that these defects were entirely 
caused in the development, and had no connection with the 
character of the collodion used, or with the preparation of 
the plate. He considered that the imperfections were pro- 
duced entirely by the repellent or nonmiscible nature of 
the solutions, containing acids and salts, used in develop- 
ment, acetic acid being one of the chief causes of the defects. 
Another source of the evil may be a low temperature and 
the developing solution being allowed to rest, even for a 
moment, on the plate. Such defects may be produced in 
abundance on any kind of dry plate if the developing 
solution is allowed to rest. 
