130 
THE GEYSERS. 
central part rises the highest, but, having gained 
some elevation, the spray divides, and darts out 
little jets on every side, that fall some way over 
the margin of the basin. After this last discharge, 
the water subsided about fifteen feet in the pipe, 
and so remained some time, but in about two hours 
the funnel was filled to within two feet of the edge. 
As often as I tried the heat of the water in the 
pipe, I always found it to be 212°; but, when 
the basin was filled, on immersing the thermo¬ 
meter as far from the margin as I could reach 
with my arm, I found the heat never more 
than 180 °; although in the centre it was boil¬ 
ing at the same time. It seems probable that 
the height to which the Geyser throws its 
waters may have increased in the course of a 
few years; as, when Sir Joseph Banks visited Ice¬ 
land in 1772, the greatest elevation to which the 
water rose, was ascertained to be sixty feet; while 
in the year 178,9? its height was taken by a qua¬ 
drant, by Sir John Stanley, and found to be 
between ninety and one hundred feet, and this 
day, if I am not mistaken, it was still greater. Po- 
velsen and Olafsen were probably deceived, when 
they imagined they saw the loftiest jets reach to 
the height of sixty toises, or three hundred and 
sixty feet. Previous to the last eruption, Jacob and 
myself amused ourselves with throwing into the 
pipe a number of large pieces of rock and tufts 
