THE ELECTROLYTIC METHOD OF CLEANING SILVER. 5 



EXPERIMENTAL STUDY OF THE METHOD. 



It was the chief purpose of these experiments to obtain information 

 as to the best metal and electrolyte to use, the most economical con- 

 centration of the solution, and the most satisfactory temperature for 

 cleaning silver as it would ordinarily be accomplished in the home, 

 and to study the relative efficiency of the electrolytic and other 

 methods. 



Throughout the investigation the methods and apparatus were 

 simple and in most cases applicable to household use, more accurate 

 procedure being deemed impracticable. In some cases silver which 

 had been naturally tarnished by use was cleaned satisfactorily by 

 this method, but in order to secure uniform conditions the silver 

 used in most tests was tarnished by immersing it in a strong 

 potassium-sulphid solution, and in order that the tarnish should be 

 uniform for a comparative series of tests, all of the spoons to be 

 used in each series were placed in the sulphid solution for the same 

 length of time. Porcelain or agate ware dishes were used for hold- 

 ing the solution of electrolyte, which was made up by adding dif- 

 ferent amounts of soda and salt, etc., to one or two quarts of water. 

 The active metal used, aluminum, or zinc, or an alloy of both, and 

 the tarnished silver were then placed in direct contact in the solution 

 which had previously been heated to the desired temperature, and 

 the time necessary for cleaning was noted by a stop watch. 



Since the preliminary tests indicated that either washing or baking 

 soda may be used as the electrolyte of the cleaning solution, it 

 seemed desirable to ascertain first of all whether either of these salts 

 was the more efficient and economical for ordinary household use. 

 Experiments were accordingly made to determine the relative effici- 

 ency of solutions of washing soda and baking soda without the addi- 

 tion of sodium chlorid. The concentration of the solutions was 1 

 teaspoonful of the commercial soda to 1 quart of water. The tem- 

 perature at which the cleaning was done was approximately 100° C. 

 in each case. In each series six spoons were used which had been 

 tarnished as described above. The following procedure was 

 MfJopted: The first spoon was cleaned in the washing-soda solution. 

 The active metal Avas then rinsed in clean water, transferred to the 

 baking-soda solution, and another spoon cleaned. By alternating 

 from one solution to the other in this way, any error in the time of 

 cleaning, resulting from the metal becoming corroded, was distrib- 

 uted equally between the two solutions. After removal from the 

 cleaning solution the spoons were rinsed in cold Avater and wiped 

 thoroughly dry with a soft cloth, rubbing very slightly. 



