436 
LORD RAYLEIGH AND MRS. H. SIDGWTCK OX THE 
root of the difference of the current weighings) by the amount of silver deposited per 
second. Thus for March 10 we have 
•95171 
. 1-0644 
“2699-4 
— 2413-7 
The magnitude of the current was about '4 ampere, and the areas of deposit about 
37 sq. centims. for the small bowls, and about 75 sq. centims. for the large bowl. 
The whole resistance of the current-weighing apparatus and of the voltameters is 
about 42 ohms, so that sufficient current can be obtained from 10 small Grove cells, or 
from a rather less number of cells of a secondary battery. 
§ 25. The tables in which are embodied the results of these protracted experiments 
will not now require much explanation. Those of Table I. are certainly erroneous on 
account of the presence of acetate (§ IS), and no weight is given to them in calculating 
a final result. For the same reason those deposits in Table II. which were prepared 
from solutions to which acetate had been added for the purpose of investigating the 
nature of the disturbance thereby produced, are of course excluded. The weights 
adopted for the silver deposits are those found after strong heating (nearly to redness) 
for about five minutes, no distinction being made between the deposits from chlorate 
and from nitrate of silver. The final mean 2414'45 expresses the square root of the 
difference of current weighings in grams divided by the rate of silver deposit in grams 
per second. 
If we consider separately the deposits from chlorate of silver (without addition of 
acetate), we get as the mean number corresponding to the above 2414’3, in almost 
perfect agreement. 
The deposits made on March 25 were twice strongly heated with intermediate 
weighing. Similar tests have been applied in other cases not recorded in the tables. 
It should be stated that every determination since November, 1883, in which the 
manipulations were successfully conducted, is included in the table, and that nothing 
is excluded except in consequence of a decision made before the result was known. 
In one or two cases the current was too irregular to give good weighings of the 
suspended coil, and then the observations were not reduced with the view of obtaining 
absolute results, although the comparison of the silver deposits in different bowls 
might still be of interest. This happened on an occasion already alluded to when 
acetate and chlorate of silver were used in combination. 
The results of Table II. agree together about as well as could be expected, the 
extreme difference from the mean being a-gVo- H must be remembered that apart 
from the difficulties of manipulating the silver deposits errors may arise in the 
determination of the current, whose mean value has to be deduced from observations 
relating to only a part of the whole time involved. A small fluctuation in the strength 
of the current, lasting for a short time only, may thus escape detection. There is also 
an error involved in the determination of the time of electrolysis, which may altogether 
