July 27, 1883.] 



SCIENCE. 



101 



costly and discouraging to prompt shippei-s ; 

 that it leads to slow movement of loaded cars 

 and to non-movement of empty ears ; that it 

 is not practised in other countries, nor does 

 any like practice obtain in any other l)n.siiiess in 

 this countiy. The per-diem basis, on the con- 

 trary, is perfect!}- practicable, as proved by two 

 years' trial on the Union Pacific, and C'iiicago, 

 Burlington, and Quiucy railroads, and its use 

 in a modified form in two European countries. 



At noon the convention adjourned. The 

 rest of the day, and Saturday, were given up 

 to the very pleasant excursions and entertain- 

 ments furnished bj- the people of the vicinity. 



If one-half as much is done to render the 

 coming meeting of the American association 

 pleasant, those who attend will find themselves 

 well entertained. 



The following table gives the results of the 

 observations in the park as far as thej' have 

 been made in regard to the points just enu- 

 merated. 



SOME GEYSER COMPARISONS. 



Havdex's twelfth annual report, pul)lished 

 by the U. S. interior deparlment, has been in 

 the printer's hands for some lime, and will 

 doubtless be shortly issued from the govern- 

 ment printing-office. Part ii. of this report 

 relates to the Yellowstone nation.il park, and 

 in it the hot-springs are fully descril)ed, and 

 the geology and topography of the park treated 

 of in detail. 



It is proposed here to point out briefly some 

 of the differences in relation to geysers be- 

 tween the results of the work in the park and 

 those reachecl by Bunsen in his study of the 

 Iceland field. It is not necessary to present 

 Bunsen's conclusions in detail, nor to describe 

 his theory, with which doubtless the ra.ijority 

 of the readers of Sciknce are familiar. 



Bunsen's conclusions, as presented here, are 

 mainly the same as stated by LeConte in his 

 J^lements of geology, although not considered 

 in the same order. 



1. Bunsen founil in Iceland two kinds of 

 springs, viz., acid springs and alkaline car- 

 bonate springs; and he says that onl}' alkaline 

 carbonate springx become siliceous, and that 

 only silicated springs form geysers. 



•2. The silica in solution does not deposit 

 on cooling, but onl}- by drying. 



Our observations in the Yellowstone nation.al 

 park in the main verify this last conclusion, 

 and it is inserted, because LeConte takes ex- 

 ce|)tion to it as follows: "This, however, is 

 not true ; for the Yellowstone geyser-waters, 

 which ' dejiosit abundantly by cooling, evidently 

 because they contain much more silica than 

 those of Iceland." 



1 This ia evidently a gramni.ilical error. 



Here, then, we have an alkaline spring and 

 an acid spring, both of which are geysers. We 

 see. also, that the mere fact of cooling has little 

 to do with the throwing down of the silica, 

 nor does the precipitation appear to be due to 

 the amount of silica held in the water. Ordi- 

 narily the formation of siliceous sinter or 

 geyserite must be explained by the evapora- 

 tion or drying of the water as it flows from the 

 springs, or fiills from the geysers. 



The chiiniiey-like form is very noticeable in 

 the craters of the Yellowstone geysers ; and 

 LeConte attributes it to the greater abundance 

 of silica in solution in the waters of the Yel- 

 lowstone geysers.' 



As a fact, however, the analyses already 

 made of geyser-waters from the park show 

 usually a smaller percentage of silica than do 

 those of Iceland. Opal spring (sec table 

 above) is an exception, and it is a spring 

 without the least apjjearance of a crater or 

 chimne\-. The real explanation is probabl}' 

 in the greater age of our gey.ser region. 



:i. Bunsen's conclusions as to temperature 

 are as follows : — 



a. The temperature increases with the depth 

 of the tube. 



b. At no point in the tube does the water 

 have the temperature of ebullition which it 

 should have under the pressure to which it is 

 subjected. 



c. The tempeiature depends on the time 

 that has elapsed since the last eruption ; and, 

 as a gi'eat eruption ai)proaches, the nearer it 

 comes to the boiling-point. 



d. At a depth of forty-five feet in the Great 

 geyser, the diti'ei'ence between the observed 

 temperature and the calculated boiling-point 

 of the water for that depth and pressure was 

 the least. 



> Elements of ijeology, p. 104. 



