190 
DR. GLADSTONE ON CIRCUMSTANCES MODIFYING 
I am disposed to think, mainly from errors in the experiment ; and this opinion is 
founded not only on the observations above detailed, but upon others of a shorter 
range, which it was not considered necessary to record, especially as the three given 
were the last of their respective kinds which 1 made, and on that account, I believe, 
worthy of the greater reliance. None of the others, I may remark, differed materially 
from them. 
I have in vain endeavoured, by the aid of my friend, Mr. Henry Watts, to find an 
equation which will resolve the curves deduced from the above observations. They 
do not appear to belong to the second order. 
For the purpose of seeing whether the same ratio was maintained where a much 
smaller proportion of red sulphocyanide was formed, the experiment was repeated 
with the ferric acetate. The following results were obtained : — 
Ferric acetate. Sulphocyan. of 
potassium. 
Red salt 
produced. 
■n • . . Sulpbocvan. of. 
Ferric acetate. ^ • 
potassium. 
Red salt 
produced. 
1 equiv.+ l equiv. 
62-4 
1 equiv.+ ll equivs. 
232 
1 equiv. + 3 equivs. 
88 
1 equiv.+ 13 equivs. 
304 
1 equiv. + 5 equivs. 
108 
1 equiv. + 1.5 equivs. 
352 
1 equiv. + 7 equivs. 
133 
1 equiv. + 19 equivs. 
398 
1 equiv. + 9 equivs. 
187 
Here we have not only an entirely different ratio, but the curve represented by these 
numbers (see the line composed of alternate lines and dots in Plate VlII. fig. 11) is of 
an irregular character. It is evident there is some interfering action ; what that is 
will be seen when the ferric acetate itself is made the subject of experiment. 
A similar experiment on the influence of mass was tried with hydrogen in the place 
of potassium ; that is to say, nitrate of iron was mixed with successive portions of a 
solution of hydrosulphocyanic acid of known strength. The following are the results 
reduced to the same unit of comparison as in the preceding cases : — 
Hydrosulpho- 
terric nitrate. 
cyanic acid. 
Red salt 
produced. 
. . . Hydrosulplio- 
Ferric nitrate. ^ , 
cyanic acid. 
Red salt 
produced. 
1 equiv. + 2 equivs. 
66 
1 equiv. + 20 equivs. 
288 
1 equiv. + 4 equivs. 
108 
1 equiv. + 24 equivs. 
315 
1 equiv. + 6 equivs. 
142 
1 equiv. + 30 equivs. 
353 
1 equiv. + 8 equivs. 
168 
1 equiv. + 38 equivs. 
400 
1 equiv.+ 12 equivs. 
217 
1 equiv. + 46 equivs. 
440 
1 equiv.+ l6 equivs. 
257 
The curve represented by these numbers is the line broken by three dots in Plate 
VHI. fig. 11. It is as regular as the corresponding one from the ferric nitrate, the 
continuous line in the same Plate, but the curve is quite different, showing a more 
rapid ratio according to which the coloured salt is formed when hydrogen is substi- 
tuted for potassium. 
Method of determining the actual amount of the coloured salt in a given mixture . — • 
From the experiments above recorded, it would seem probable that no amount of sul- 
