No. 3 
RETORT UPON AN ANALYTICAL EXAMINATION OF WATER AND MINE¬ 
RALS FROM THE HOT SPRINGS IN DES CHUTES VALLEY. 
CONDUCTED UNDER THE DIRECTION OF PROF. E. N. HORSFORD.* 
LETTER FROM PROF. E. N. HORSFORD. 
Harvard University, Cambridge, May 25, 1857. 
Sir : I enclose to you the report of my assistant, Mr. L. M. Dornbach, upon the minerals and 
■water of the hot siliceous springs of the Des Chutes valley, Oregon, which you placed in my 
hands. 
I am, very respectfully, yours, 
Lieut. H. L. Abbot, TJ. S. Top. Engs. 
E. N. HORSFORD. 
REPORT BY MR. L. M. DORNBACH. 
The notes accompanying the specimens are as follows : 
“ The sample of water is taken from one of a number of thermal springs which give a peculiar 
character to a region some miles in extent. The temperature of the water is about 145° Fahr., 
and the basins into which it flows are filled with floating jelly-like masses of silica. A white 
incrustation is formed upon all objects lying in the water. The volcanic tufas in the vicinity of 
the springs are accurately stratified, horizontal, and nowhere disturbed. The stream and hot 
water from the springs have penetrated the strata in all directions, producing complete meta¬ 
morphosis of the different materials of which they are composed, converting the porous pulveru¬ 
lent tufas, by a succession of changes, into a kind of jasper.” 
The method adopted in the qualitative analysis for the detection of the alkalies was to fuse 
one part of the finely pulverized mineral with four parts of a mixture of three parts of carbonate 
of baryta and one part chloride of barium. The fused mass was next digested with hydrochloric 
acid to decompose the silicate of baryta ; then evaporated to dryness to expel most of the free 
acid, treated with water and the silica filtered off. The baryta, with the iron, lime and alumina 
was precipitated by adding carbonate of ammonia, the filtrate was then evaporated to dry¬ 
ness, the ammoniacal salts expelled, and the chloride of magnesium converted into insoluble mag- 
* Note by Lieut. Abbot .—It is proper to state that Prof. Horsford conducted these analyses in his laboratory, without ex¬ 
pense to the government. The specimens were collected at the most interesting locality upon our route, in a geological 
point of view, and the results of the analysis are of great value in illustrating the action of thermal springs. 
