384 



SCIENCE. 



[Vol. XIII. No. 328 



nection with a study of the geysers. The altitudes of the geyser 

 basins above sea-level have been ascertained by long series of 

 barometric readings, continued through several seasons. In con- 

 ducting a series of observations upon the boiling-points of the 

 thermal waters in the park, Dr. William Hallock, who had charge 

 of this special investigation, determined the theoretical boiling-point 

 by noting the mean daily readings of the mercurial column. The 

 exact boiling-point of a pure surface-water, obtained from a neigh- 

 boring mountain-stream, and the boiling-point of the thermal 

 waters from the springs, were determined from actual experiments 

 by heating over a fire, employing every possible precaution to avoid 

 sources of error. Surface-waters and deep-seated mineral waters 

 gave the same results, and coincided v\'ith the calculated boiling- 

 point at this altitude. Hundreds of observations have been care- 

 fully taken where the waters in the active and running springs 

 boiled at temperatures between 198° and 199° F. 



As will be shown later in this paper, the thermal waters are 

 solutions of mineral matter too dilute to be affected to any appreci- 

 able extent as regards their boiling-point by their dissolved con- 

 tents. The theoretical boiling-point for the springs and pools in 

 the Upper Geyser Basin may be taken at 92.5° C. (198.5° F.). In 

 many of the large caldrons, where the water remains quiet, a tem- 

 perature has been recorded of 94° C. (201.2° F.) without the usual 

 phenomena of boiling. This gives a body of superheated water, 

 with a temperature at the surface of 1.5° C. (2.7° F.) above the point 

 necessary to produce explosive action. Thermometers plunged 

 into the basins show slightly varying temperatures, dependent upon 

 their position in the basin. They indicate the existence of numer- 

 ous currents, and a very unstable equilibrium of the heated waters, 

 which are liable, under slight changes, to burst forth with more or 

 less violence. It is under these conditions that geyser-action can 

 be accelerated by artificial means. If into one of these superheated 

 basins a handful of sinter pebbles be thrown, or the surface of the 

 water be agitated by the rapid motion of a stick or cane, or even 

 by lashing with a rope, a liberation of steam ensues. This is 

 liable to be followed by a long boiling of the water in the pool, 

 which in turn may lead to geyser-action. There is some reason to 

 believe that, at least in one instance, an eruption has been brought 

 about by a violent but temporary gust of wind, which either ruffled 

 the water or disturbed the equilibrium of the pool, and changed 

 momentarily the atmospheric pressure. 



In Iceland, travellers have long been accustomed to throw into 

 the geysers turf and soft earth from the bogs and meadows which 

 abound in the neighborhood, the effect produced being much the 

 same as that of sinter pebbles and gravel upon the geysers in the 

 National Park. So well was this understood, that at one time a 

 peasant living near the Iceland locality kept a shovel solely for the 

 accommodation of those visiting the geysers. 



In my letter to Dr. Raymond, I mention the curious fact that the 

 laundryman's spring, now known as the Chinaman, in which gey- 

 ser-action may most easily be produced by artificial means, has 

 never been regarded by the Geological Survey as any thing but a 

 hot-spring; and no one has ever seen it in action without the ap- 

 pUcation of soap, except in one instance, when it was made to play 

 to a height of twenty feet after stirring it vigorously with a pine 

 bough for nearly ten minutes. In our records it is simply known as 

 a spring. 



If soap or lye is thrown into most of the small pools, a viscous 

 fluid is formed ; and viscosity is, I think, the principal cause in 

 hastening geyser-action. Viscosity must tend to the retention of 

 steam withm the basin, and, as in the case of the superheated 

 waters, where the temperature stands at or above the boiling-point, 

 explosive liberation must follow. All alkaline solutions, whether 

 in the laboratory or in nature, exhibit, by reason of this viscosity, a 

 tendency to bump and boil irregularly. Viscosity in these hot- 

 springs must also tend to the formation of bubbles and foam when 

 the steam rises to the surface ; and this, in turn, aids to bring 

 about the explosive action, followed by a relief of pressure, and 

 thus to hasten the final and more powerful display. Of course, 

 relief of pressure of the superincumbent waters upon the column 

 of water below the surface basin is essential to all eruptive action. 

 These conditions, it seems to me, are purely physical. Undoubt- 

 edly the fatty substances contained in soap aid the alkali in ren- 



dering the water viscous. On the other hand, when concentrated 

 lye is used, it acts with greater energy, and furnishes a viscous 

 fluid where soap would yield only surface suds, insufficient to ac- 

 complish any phenomenal display. 



It is well known that saturated solutions of mineral substances 

 raise the boiling-point very considerably, the temperature having 

 been determined for many of the alkaline salts. In general, I be- 

 lieve the boiling-point increases in proportion to the amount of salt 

 held in solution. Actual tests have shown that the normal boiling- 

 point of silicious waters in the park does not differ appreciably from 

 the ordinary surface-waters ; mainly, I suppose, because they are 

 extremely dilute solutions. 



The amount of lye required to produce a sufficiently viscous con- 

 dition of the waters increases but slightly the percentage of mineral 

 matter held in solution. 



All the waters of the principal geyser-basins present the closest 

 resemblance in chemical composition, and, for the purposes of this 

 paper, may be considered as identical in their constituents. They 

 have a common origin, being, for the most part, surface-waters 

 which have percolated downward for a sufficient distance to come 

 in contact with large volumes of steam ascending from still greater 

 depths. The mineral contents of the hot-springs are mainly de- 

 rived from the acid lavas of the park plateau, as the result of the 

 action of the ascending steam and superheated waters upon the 

 rocks below. These thermal waters are essentially silicious alka- 

 line waters, carrying the same constituents in somewhat varying 

 quantities, but always dilute solutions, never exceeding two grams 

 of mineral matter per kilogram of water. When cold, they are 

 potable waters, for the most part slightly alkaline to the taste, and 

 probably wholesome enough, unless taken daily for a long period 

 of time. 



Dr. Raymond has made the suggestion that the addition of 

 caustic alkali would possibly precipitate some of the mineral in- 

 gredients found in these waters, thereby changing their chemical 

 composition sufficiently to affect the point of ebullition. At the 

 same time he remarks that the geyser-waters are probably too 

 dilute solutions to be much influenced by such additions. Any 

 one who glances at the analyses of the waters of the Bee-Hive, 

 Fountain, and Fearless must see, I think, that they are not only too 

 dilute to undergo any marked change of temperature, but that the 

 mineral constituents consist mainly of the carbonates and chlorides 

 of the alkalies, associated with a relatively large amount of free 

 silica, which would remain unacted upon by caustic alkali. There 

 is nothing in the waters to be thrown down by the addition of 

 alkali, or to permit any chemical combinations to be formed by the 

 addition of a small amount of soap. The desire of tourists to 

 " soap a geyser " during their trip through the park grows an- 

 nually with the increase of travel ; so much so, that there is a 

 steady demand for the toilet-soap of the hotels. If visitors could 

 have their way, the beautiful blue springs and basins of the geysers 

 would be " in the suds " constantly throughout the season. Throw- 

 ing any thing into the hot-springs is now prohibited by the gov- 

 ernment authorities. It is certainly detrimental to the preservation 

 of the geysers, and the practice cannot be too strongly condemned 

 by all interested in the National Reservation. 



THE EAST GREENLANDERS. 



Capt. Holm's expedition to East Greenland was as remarka- 

 ble on account of its geographical results as in regard to the eth- 

 nological observations made among the isolated tribes of the 

 northern parts of the east coast of Greenland. The results of his 

 journey have been published, and form the tenth volume of the 

 " IMeddelelser om Gronland." In a recent number we referred to 

 the linguistic and folk-loristic papers. Of no less importance are 

 the general anthropometric and ethnographical results of the expe- 

 dition. 



Dr. Soeren Nansen has submitted the craniological material and 

 the measurements of Capt. Holm to an elaborate discussion, from 

 which we glean the following facts. The whole population con- 

 sisted of 548 heads, 245 of whom were males, while 303 were fe- 

 males. The size of the people is below the average, being 1,647 

 millimetres ; while in the southern parts of the coast the average 



