TRANSACTIONS OF SECTION C. 157 



stations to the meridian and perpendicular of the trig, station. 

 The changes at the terminal face are principally owing to the 

 Hooker Eiver, which continually alters its course, sometimes 

 running under the ice, as it did in 1889, but more often simply 

 following it round. Whichever way it runs, the effect is the 

 same : the ice is eaten away underneath, especially in flood- 

 time, the upper part falls, and great blocks of ice are carried 

 away by the river. I have found them stranded seven miles 

 lower down. I draw your attention to this, for otherwise it 

 would be dilScult to account for the great and constant changes 

 which take place. No doubt a larger amount of snow than 

 usual falling in any particular year would eventually find its 

 way to the terminal face and cause an advance : but the Mueller 

 Glacier on account of the river is unsuitable for any experi- 

 ments at its terminal face ; it is also rough and difficult to 

 traverse, but I have carried out your instructions, and traversed 

 it as closely as I was able. While on this subject I may 

 remark that, accepting the mean annual rate of all the stones 

 as a fair basis for determining the speed of the glacier (that is,- 

 twenty-six years to a mile), and allowing that the snow which 

 falls nearer the terminal face than four miles is either melted 

 by the heat or wasted away by surface-streams, and that 

 Mount Sefton contributes nothing to the general stream within 

 three miles of the face, then the snow which forms the most 

 northerly portion of the terminal ice fell eighty years ago, that 

 at the middle might vary between one hundred and two hundred 

 years ago, but none of it would be under one hundred years 

 old. The most southerly portion would be between one 

 hundred and one hundred and thirty years of age. I believe I 

 am correct in saying this, because I take it that, when two 

 glaciers meet, although they join together and form one stream 

 they never mingle. I do not know whether this fact would be 

 disputed, I am too far away to be able to refer to any authority 

 on the subject, but a glance at the tracing of the Murchison 

 Glacier, and a perusal of my description of its moraines, will 

 convince any one that such is the case. As an instance of the 

 magnitude of the ancient glaciers, and the time they must have 

 occupied this valley, it will suffice to say that, at the same rate 

 of speed as the Mueller, the glacier which formed the moraine 

 south of the Pukaki Lake took eight hundred years to carry a 

 stone from the present terminal face of the Tasman to that 

 place. I should say that the average thickness of the moraine 

 lying on the Mueller is about 18in. : it would be possible to 

 calculate approximately how long it took this glacier to build 

 up the large moraines between which it now flows." 



As the declivity of the Mueller Glacier at the place where 

 the observations were taken is very much greater (the glacier 

 showing a fall of over dOOft. to the mile) than the bed on which 



