348 QUICKSILVER DEPOSITS OF TUE PACIFIC SLOPE. 



iiKTcury was j)recii)itate(l by pliosplidrcnis acid under coiulitions precluding' 

 tlie precipitation of any other metal. A taint cloudiness indicated its pres- 

 ence, but no weigliable quantity came down. 



The basin from which this water was taken was small and contained 

 perliaps no more than a cubic .foot of water; but the overHow was also 

 small, and a part of the water in it must have been exposed to the air at a 

 high temjierature for a considerable time. Some decomposition was there- 

 fore to be expected. If solutions of alkaline suljdiides be allowed to oxi- 

 dize, h^-posuljdiites are well known to form. The analysis shows hyposul- 

 pluirous acid, and this, I think, must be attributed to decomposition, for 

 its formation at great depths appears hard to explain, nor am I aware that 

 hyposulphites have ever been detected under conditions which suggest their 

 existence in nature at points removed from oxidizing influences of the air. 

 The hyposulphurous acid is undoubtedly combined with sodium, and prob- 

 ably represents a certain amount of oxidized sodimn sulphydrate. The 

 decomposition of sodium sulphydrate is well known to be attended by the 

 foi'niation of sodic hydrate. The antimony and arsenic were certainly in 

 solution, and it is altogether probable that they were originally in the form 

 of sulphai"senides and sulphantimonides of sodium. But in the presence of 

 caustic soda these sulphides are partially decomposed with the formation of 

 arsenites and antimonites The sum of the quantities of sulphur found in 

 combination with metals and in the free state or in combination with hy- 

 drogen is just sufficient to form sulphantimonides and sulphar.senide of 

 sodium, and the presence of hydrogen sulphide is explained if one supposes 

 the sulphosalts partially decomposed, as suggested above. In the table 

 given below I have supposed the arsenic and antimony to be entirely in the 

 condition of sulphosalts and that the h}posulphite is represented by sodium 

 sulphydrate. As has been mentioned, silica is precipitated when this water 

 is cooled ; but when tlie fluid reaches the surface there can be little doubt 

 that it all exists in combination with the alkalis as an acid silicate. It 

 is not improbable that this compound is the quadrisilicate of sodium It is 

 computed as such. 



Acid sodium carbonate is well known to be partially decomposed at 

 high temperatures, and it is therefore by no means unreasonable to suppose 



