ON THE SEPARATION OF SOME ACIDS. 
179 
The alloy of gold and silver which it contains consists 
consequently of — 
T. H. Henry obtained 
Gold 909-66 Gold 90-01 
Silver 90-34 Silver 9-01 
Copper 0-86 
and corresponds to an alloy of 21-48 carats. On comparing 
the author's analysis with that of Henry, it is evident that 
the Californian gold does not occur everywhere alike as 
regards the amount of silver; and that the accompanying 
constituents are not in all cases the same, but vary either 
with the nature of the soil, or with the greater or less care 
employed in the washing. — Chemical Gazette, January 
15, \850.fro?n Poggendorff ? s Annalen, lxxviii. p. 96. 
ART XLV.— ON THE SEPARATION OF SOME ACIDS OF THE 
SERIES (CH) "0* . 
By Prof. J. Liebig. 
In order to discover small quantities of butyric and vale- 
rianic acids in an acid mixture of the two, and to obtain the 
acids in a fit state for analysis, the following plan is most 
advantageous : — 
A portion of the acid mixture is saturated with potash 
or soda, the remaining portion of the acid is added to the 
neutralized portion, and the whole subjected to distillation. 
Two cases now occur; if the valerianic acid in the mixture 
amount to more than is sufficient to neutralize the whole 
of the alkali, the residue contains no butyric acid, but pure 
valerianic acid. If the quantity of valerianic acid be less, 
a proportionate amount of butyric acid is left with the 
whole of the valerianic acid in the residue, but the distillate 
consists of pure butyric acid. 
The quantity of the mixed acids which is neutralized 
