310 Headden— Brown Artesian Waters of Costilla Co., Colo. 



surface origin than a deep-seated one, for while the waters of 

 our mountain streams are not so rich, even relatively, in 

 potash salts as this lake water, they approach it much more 

 nearly than any others known to me. In cases where the 

 watersheds are composed of granites, gneisses and schists, in 

 which the predominant feldspar is orthoclase, we find the waters 

 characterized by a low mineral content consisting of much 

 silicic acid and a relatively large amount of potash. These 

 two characteristics are present in this water, the former, how- 

 ever, not in a very marked degree, but the latter strongly so. 



The question whether the silicic acid may have separated 

 from this water as a difficultly soluble silicate is one on which 

 the deportment of similar water under pressure, for instance 

 when used in steam boilers, may throw a little light. In sev- 

 eral cases which have come under my observation I have found 

 the incrustation formed to consist very largely of silica. In 

 one case in which the boiler had been in service for four years 

 and had been fed with artesian water coming from two differ- 

 ent flows bnt of essentially the same character, the incrustation 

 formed on the boiler tubes was one quarter of an inch in 

 thickness and consisted of silicic acid and lime, 76 per cent of 

 the former and 24 per cent of the latter, including a small 

 amount of alkalies. Some such separation may have removed 

 a part of the silicic acid from the lake water, in which there is 

 at the present time only a small amount of lime, one grain per 

 gallon. 



The ammonia determinations in the sanitary analysis of this 

 water presented peculiar and greater difficulties than I had 

 ever met with in a water. The water is colorless and not 

 strongly alkaline. There is no suggestion of the presence of 

 humus : -the slowness and persistency with which the ammonia 

 distilled over was the only suggestion of its presence. It has 

 been suggested that when successive, equal portions of the dis- 

 tillate show about one half as much ammonia as the preceding 

 one, the probable presence of humus is indicated. According 

 to this criterion the first three portions indicated the presence 

 of humus, but each of the next six portions contained equal 

 amounts of ammonia and no end of the reaction was obtained. 

 In the distillation of the albuminoidal ammonia distilled water 

 (ammonia free) was added, and 14 portions of 50 cc each were 

 distilled over without obtaining an end to the reaction. The 

 organic matter indicated by the slow and persistent evolution 

 of ammonia may have come from a variety of sources, for the 

 lake abounds in vegetation and, as I am credibly informed, in 

 other aquatic life, a small fish attaining a length of Ave or six 

 inches being especially abundant. As there is no outlet to this 

 lake, it is evident that the water must become heavily charged 



