51.4 
Proceedings of the Royal Society 
Monday , 19 th April 1875. 
Sir WILLIAM THOMSON, President, in the Chair. 
The following Communications were read : — 
1. Note of Temperature Measurements in the Great Geysir 
of Iceland — August, 1874. By Bobert Walker, Esq. 
I have thought it might be of interest to the Society to lay before 
it a short account of some temperature observations which I suc- 
ceeded in making at the Great Geysir of Iceland, in the month 
of August last year. As the circumstances of my visit to the 
island obliged me to limit my stay at that remarkable spring to a 
few hours, and as, during that time and for 48 hours previously, 
no great eruption occurred, I fear my results must appear some- 
what meagre and unsatisfactory. The very interesting nature, 
however, of the problem of the action of the Great Geysir, and 
the difficulty of securing any reliable observations at all in so inac- 
cessible a region, will perhaps be deemed sufficient grounds for 
my taking up the time of the Society with these few remarks. 
So far as my results go, they confirm very remarkably those of 
Professor K. Bunsen, who, with a companion, spent more than ten 
days at the spot in July 1846, and to whom science is indebted 
for the now generally received theory of the action of the Great 
Geysir. An account of his observations was given in the “Annalen” 
for 1847, and to it I shall refer frequently in the course of these 
remarks. 
If the difficulty of obtaining thermometer readings at various 
points in a column of water from 70 to 80 feet deep, and more or 
less in a constant state of agitation, be great, the difficulty of 
reaching the place at all I found to be by no means inconsiderable. 
Arriving in Reykjavik on the afternoon of Monday, 3d August, 
after a very stormy passage of nearly five days from the Clyde, we 
experienced, owing to the visit of His Majesty the King of Den- 
mark, more than the usual trouble and delay in securing guides 
and ponies, for the long ride of nearly 80 miles up country. It is 
