THE ELECTROLYTIC METHOD OF CLEANING SILVER. 
Table I. — Comparative efficiency of solutions of washing and baking soda at 
the boiling temperature — Continued. 
Solution. 
Time required for 
cleaning. 
Remarks. 
Observed. 
Average. 
Series 9. 
Washing soda 
Do 
Seconds. 
5 
4 
2.5 
4 
4 
5.5 
4 
3 
2 
2 
3 
3 
5 
4 
5 
3 
3.5 
4.5 
3 
5 
6 
5 
7 
11 
Seconds. 
1 4 
1 4 
I 3 
1 3 
1 5 
1 4 
1 5 
1 8 
( The aluminum used in series 9 had been cleaned by polishing 
\ with emery cloth. 
Do 
Baking soda 
Do 
Do 
- 
Series 10. 
Washing soda 
Do 
[In series 10, 11, and 12 the active metal used was zinc. In series 
Do 
Baking soda 
Do 
Do 
Series 11. 
Washing soda 
Do 
Do.... 
Baking soda 
Do 
Do 
Series 12. 
Washing soda 
Do 
/The zinc had been standing in the hot cleaning solution for 10 
\ minutes before use in series 12 and was not cleaned with acid. 
Do 
Baking soda 
Do 
Do 
From the results of these experiments it is evident that washing 
soda is slightly more efficient than baking soda, the average time re- 
quired, considering all of the tests, being 9J seconds for the washing- 
soda solution and 10J seconds for the baking-soda solution. For all 
practical purposes, since the difference between the efficiency of wash- 
ing soda and that of baking soda is so small as to be within the limits 
of experimental error, it may be considered feasible to use them in- 
terchangeably. As far as the appearance of the cleaned spoons was 
concerned, no difference was noted in the two solutions ; all the spoons 
that were cleaned showed a bright satin finish after each cleaning and 
were practically as bright at the end of each experiment as at the 
start. Washing soda is somewhat more economical, since it is more 
efficient and cheaper as well. 
The next factor to be considered was the effect of increasing the 
conductivity of the cleaning solution, and common salt was used for 
this purpose. In the following experiments the silver to be cleaned 
was uniformly tarnished by immersing the spoons in the same tarn- 
ishing solution for the same length of time. In some of the tests alu- 
