408 KEPOET UNITED STATES GEOLOGICAL SUEVEY. 



fusion with carbonate of soda I separated 0.8825 grams of silica =80.22 per cent. ; next 

 0.03'o grams of a mixture of alumina and sequioxide of iron = 3.27 per cent. ; iinally, 

 0.005 grams of Iime=0.45 percent. The manganese and magnesia were not deler- 

 mined in quantity, but are counted into the lo88 = 1.15 per cent. 

 Bringing the results into a column : 



Per cent. 



Silica 80.22 



Alumina and iron '.i.'zl 



Lime 0. 45 



Loss on ignition 14. 91 



Manganese, magnesia, and loss 1. 15 



From these datas the original substance would have the following composition : 



Per cent. 



Water 75.43 



Silica. 19.71 



Alumina and iron oxide 0.80 



Lime 0.11 



Organic matter 3.67 



Manganese, magnesia, and loss 0,28 



The water and silica make up the principal part. It is ^95.14 per cent., and the 

 remaining substances seem to be mixed with this hydrosilicic acid. The pure hydro- 

 silicic acid would therefore have the composition : Silica = 20.72 per cent., oxygen = 

 11. 04 percent., water = 79.28per cent., oxygen = 70.47 per cent. Theratioll.04 : 70.47 

 1 : 6.38 may serve to formulate the compound. 



[(Si)H".] 



* 



It is very probable that this compound possesses no stability when exposed to a dry 

 atmosphere. Part of the water will evaporate and thus change the relative proportions 

 of its constituents. The same is the case with other hydrous minerals. The object in 

 view was to determine the soft, flesh-like looking unknown substance just as it was col- 

 lected and received. The name suggested is nothing but a fancy on account of its 

 peculiar appearance as the substance represents itself. 



Beneath the microscope the substance appears, by transmitted light, in very small, 

 rounded, and occasionally in elongated granules, which reminded me of the yeast 

 plant, so far as the form is concerned, but its soiu'ce and composition excludes the idea 

 of being that organic matter. 



GEYSEKITES. 



Under this head are presented the analyses of the recent deposits of 

 the geysers and springs of the Park. These were made by Dr. Leif- 

 mann. A large collection of specimens was brought in, but as we could 

 only have a limited number of analyses made, we selected specimens 

 mainly from those places from which specimens had never been analyzed. 

 Specimens from the other parts of the Park were analyzed in previous 

 years, and the results are incorporated in the tables which follow the 

 analyses enumerated here. The latter will be considered according to 

 their localities. 



Upper Geyser Basin of Fire Sole River. 



The only analysis we present is of a specimen from spring No. 24 in 

 the Three Crater Group. It is a red-mud spring, which is at the bot- 

 tom of a cave-like depression. The water is a thin reddish mud, which 

 splashes against the sides, forming red stalagmitic processes or points. 



ANALYSIS. 



(Color, red; fracture, uneven; hardness, 4.) 



Per cent. 



Silica 86.9 



Water and organic matter 8. 



Iron and aluminum susquioxides - 3. 6 



98.5 



* Expressed in modern formula, H4Si04-f 11 H2O. 



