CHAPTER IX.

On a Mode of Printing Enlarged and Reduced Positives, Transparencies, &c., from Collodion Negatives--On the Use of Alcohol for Sensitizing Paper--Recovery of Silver from Waste Solutions,--from the Black Deposit of Hypo Baths, &c.--The Salting and Albumenizing Paper--On the Use of Test Papers--Comparison of British and French Weights and Measures 191