186 
same year, it is stated that the prints were fixed in a weak 
solutien of iodide of potassium. Ammonia had been tried, 
but not very successfully, but the method preferred was a 
strong solution of common salt. It will be seen, therefore, 
that up to the date of the publication of Sir John Herschel’s 
paper hyposulphite of soda had not been used in photography 
excepting by himself. 
