346 QUICKSILVER DEPOSITS OF THE PACIFIC SLOPE. 



Free sulphur occurs at many of the springs and also at tne mine. It 

 is of course produced by the partial oxidation of hydrogen sulphides, either 

 by atmospheric air or by sulphurous anhydride. The quantity is nowhere 

 large, and I doubt whether more than a pound or two could be collected 

 at any one spot. In this respect there is a great difference between this 

 locality and Sulphur Bank, where a great quantity of sulphur was exploited. 

 The sulphur is found chiefly at points to which the access of air is liniiteJ, 

 as should be the case according to the thermocheniical relations stated on 

 page 255. 



The water. — Tlic wflter anuhzcd was taken from a spring at the eastern 

 edge of the sinter plateau, which had formed a basin. The water in the 

 basin seemed perfectly limpid and the overflow was gentle and nearly con- 

 stant. The temj)erature of the spring was found to vary considerably, the 

 extreme limits noted being 75*^ and S4.5° C. In order that the water might 

 be free from solid impurities it was siphoned off from the basin into a 

 covered funnel and was filtered directly into the demijohns used to ti-ans- 

 port it. In passing through the siphon the water was inevitably cooled, 

 and it was found that the water on the filter paper had a temperature of 

 from 30.5° to 33° C. In collecting the water in this manner a very inter- 

 esting fact was observed. Near tlie lower end of the glass siphon a red 

 precipitate formed. Since neither air nor any other foreign substance had 

 access to the water at this point, the precipitation could hardly be attributed 

 to any other cause than cooling. The precipitate consisted of sulphides of 

 antimony and arsenic and silica, the last being deposited chiefly on the 

 ujiper part of the coated portion of the tube. Here, then, ores and one of 

 the most important of gangue nn'nerals were deposited in an opening b}' 

 natural means, and I had the pleasure' of watching the actual progress of 

 the formation of an ore deposit. On the filter paper also a similar precipitate 

 formed, but here the organic matter of the paper and atmospheric influences 

 were at work, and floating dust came in contact with the fluid. Even the 

 water in the spring basin must have contained organic germs, for at all the 

 springs, so soon as the water has somewhat cooled, low forms of vegetable 

 life flourish and form red and green, ])ul])y sheets of slimy matter. The 

 germs of these organisms are no doubt abundant in the atmosphere and fall 



