150 



GEOLOGICAL SUEVEY OF THE TEREITORIES. 



on top. The orifice of the geyser-tnbe is circular and 3 feet iu diameter, 

 and its throat is lined with large globular masses, of an orange-color, and 

 beautifully beaded, as is seen so universally throughont bo<:h geyser- 

 basins. An ernption is as follows: It commences with a snccession of 

 jets of water, in number abont twenty per minute, which rise to various 

 heights. These last about fifteen minutes and are succeeded by steam, 

 mingled with spray, whicli escapes with a sort of pulsating movenu^ut. 

 This soon changes to a steady escape. It seems as though the water 

 were exhausted and the steam was being forced out as rapidly as pos- 

 sible. This again clianges, and the steam escapes in cloud like masses 

 with a roaring sound, like the escai)e of steam from some vast escape- 

 pipe, which in reality it is. This gradually dies away and the eruption 

 is ended, having lasted about an hour and twenty minutes. We wit- 

 nessed one full eruption and i)arts of two others, as follows : 



First eniption, August 18. — Maximum height, 34 feet ; mean height, 21 

 feet. 



Second ernption, August 19. — 10.3.0 a. m., commencement; 10.G.40 

 a. m,, maximum of water-period, height 93 feet; 10,18 a. m., maxi- 

 mum of steam, height lla feet; 11.25 a. m., end of eruption. 

 Mean height of water, 57 feet ; of steam, 81 feet. 

 Third eruption^ August 20. — 7.21 a. m., eruption began; 7.40.20 a.m., 

 eruption ended. 



We did not see the beginning of the first eruption, and did not, there- 

 fore, wait until it was over. The angles for height were taken from the 

 end of a base-line of 100 feet, measured from the center of the orifice, 

 and the heights are above the end of the base-line. The third was wit- 

 nessed from a distance, and the height was not ascertained. At the 

 base of the Castle there is a spring, measuring 12 feet by 7 feet, 

 which bubbles intermittently. The water was at the boiling point, 

 (199°;) air, 04° F.. at 11.35 a. m. Twelve feet from this there is a second 

 spring of the same character, measuring G feet by 3 feet and having a 

 temperature of 192° F. The bed of the stream flowing from these 

 springs is coated with bright-red oxide of iron. The water in these 

 s])rings rose and fell repeatedly during the eruption of the Castle. 

 While steam mingled with spray escaped from the Castle the water 



was out of sight in 

 these springs, and 

 when steam alone es- 

 caped they were ac- 

 tive, sj)urting to the 

 heightof 3 fe'et. The 

 principal spring near 

 the Castle is a large 

 blue spring, almost 

 circular in shape, 

 n)easuring 19 by 21 

 feet. It has a most 

 regular and beautiful 

 scalloped eilgo, and 

 looks as though it 



KIM ABOUT A GEYSEK-TUCE, UPPER FIRE-HOLE. WCrC liucd Wltlj WllltC 



marble. This white basin slopes to a large funnel-shaped orifice, which is 

 on the side next the Castle. This is 40 feet deep. The surface of the water 

 is placid and appears of a most intense blue, especially over the orifice. 

 The temperature of the Avater was 180o F. ; air, 58° F., at 9.08 a. m. Fig. 

 37 is an illustration of one of the springs near the Castle, showing the ap- 





\'. 



\ UJ 



^^ 



% 



^^m^l ^^ --^;>>/-/rr-w>A4 JU 



":^C^- 





