UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 449 
Contribution from the States Relations Service 
J^^^-Ti. A. C. TRUE, Director 
Washington, D. C. 
PROFESSIONAL PAPER 
October 31, 1916 
A STUDY OF THE ELECTROLYTIC METHOD OF 
SILVER CLEANING. 1 
By H. L. Lang and C. F. Walton, Jr., Scientific Assistants, Office of Home 
Economics. 
CONTENTS. 
Page. 
Introduction 1 
Preliminary tests 3 
Principle of the electrolytic method 4 
Page. 
Experimental study of the method 5 
A household method 11 
Summary 11 
INTRODUCTION. 
An understanding of the factors which influence the tarnishing 
of metals and a knowledge of efficient methods for removing tarnish 
are necessary for the proper care of household equipment. An ex- 
tended study of these problems, therefore, is being made by the 
Office of Home Economics, and the work reported in this paper is 
a part of this investigation. 
The tarnishing of metals in general is due to the formation of 
oxids or basic oxids of the metals by the chemical action of the 
oxygen and water vapor of the air to which they are exposed. In 
the light of recent investigations a distinction is made between 
rusting, or oxidation, and the corrosion of metals. Thus, the rust- 
ing of iron may be regarded as taking place in two steps: The dis- 
placement of the hydrogen ions of water with the formation of a 
small amount of soluble iron salts in the lower state of oxidation 
is technically termed corrosion, while true rusting is the oxidation 
1 Prepared under the direction of C. F. Langworthy, Chief, Office of Home Economics. 
Note. — This bulletin contains information regarding the advantages and limitations of 
the electrolytic method of cleaning silver and the conditions under which it is most 
efficient, which it is believed will prove useful to teachers and housekeepers generally. 
59849°— Bull. 449—16 
