6 BULLETIN 449, U. S. DEPARTMENT OF AGEICULTUEE. 
Table I shows the results of the tests : 
Table 1. — Comparative efficiency of solutions of washing and baking soda at 
the boiling temperature. 
Solution. 
\ Time required for 
cleaning. 
Series 1. 
Washing soda . 
Do 
Do 
Baking soda... 
Do 
Do 
Series 2. 
Washing soda. 
Do 
Do 
Baking soda... 
Do 
Do 
Series S. 
Washing soda. 
Do 
Do 
Baking soda... 
Do 
Do 
-Series 4. 
Washing soda . 
Do 
Do 
Baking soda... 
Do 
Do 
Series 5. 
Washing soda. 
Do 
Do 
Baking soda.. 
Do 
Do 
Series 6. 
Washing soda . 
Baking soda... 
Series 7. 
Washing soda . 
Do 
Do 
Baking soda.. 
Do 
Do 
Series S. 
Washing soda . 
Do 
Do 
Baking soda.. 
Do 
Do 
Remarks. 
Observed.. Average. 
Seconds. \ Seconds. 
30 
10 16 ; Zinc was the active metal used in series 1, 2, and I 
240 
20 
15 
17 
10 
9 
150 
10 
10 
12 
10 
13.5 
11 
4.5 
2 
7. 5 
4.5 
IS 
12 
The exceptionally long time required in the first test of series 2 
and 3 was due to the zinc becoming corroded: it was necessary 
to substitute a strip of clean zinc before the tarnish was 
removed. In such cases the time has been disregarded in 
computing the average. 
10 Aluminum was the active metal used in series 4 to 9. inclusive. 
fin series 7 and S a small sheet of very pure aluminum of the 
spun variety was used. 
