220 J. P. Cooke—Solubility of Chloride of Silver in Water. 
Art. XX VIIL— On the Solubility of Chloride of Silver in Water; 
by Jostan P. Cooke. (Contributions from the Chemical 
Laboratory of Harvard College.) 
Ts subject has already been studied by Stas, whose obser- 
vations are summed up by Dr. John Percy* in his recent vol- 
ume on the Metallurgy of Silver in the following words: 
“The solubility of the chloride is greatest when in the flaky 
state, as precipitated in the cold from a sufficiently dilate solu- 
tion of silver; the solubility diminishes as the flakes shrin 
when left to themselves, or as they are rendered pulverulent by 
long agitation with water. Flaky or pulverulent chloride of 
silver, dissolved in water pure or acidified by nitric acid, 18 
precipitated by the addition of a salt of silver or of h ydrochlori¢ 
id or of an alkaline chloride.” . . . “The solution of the 
ride in proportion to the quantity of acid present. The precip! 
tation of the dissolved chloride is the exclusive result of its 
insolubility in the solution formed by adding an excess either 
of the silver salt or of the alkaline chloride.” : 
So also in Liebig and Kopp, Jahresbericht, 1871, 339: 
“ According to Stas, the granular scaly and crystalline chlo- 
ride is wholly insoluble in cold water: in boiling water the solu- 
bility is comparatively great, but decreases rapidly with the 
temperature.” 
In our investigation on the atomic weight of antimony yer 
have had oceasion to confirm and extend these observations ° 
Stas, and our results may be of interest as showing that 1 the 
very familiar method of determining chlorine by precipitation 
with nitrate of silver, which is generally supposed to 
extremely accurate, a sensible error may arise from the so! 
bility of the chloride of silver in the hot distilled water used 10 
washing the precipitate. It would be well for every analyst t 
make the following very striking experiment, which will ena- 
ble him to appreciate the extent of the action in question. 
Take from five to ten cubic centimeters of pure hydrochlorie 
acid and precipitate the chlorine in the usual way with nitrate 
of silver, avoudin a large excess. After pouring off the melee 
natant liquid and washing the precipitate once or twice be 
cold distilled water, pour upon the white flaky chloride of st” 
ver a comparatively large volume of boiling water. As 800? 
* Metallurgy of Silver and Gold. Part I, page 60. 
