156 AMUND HELLAND ON THE FJORDS, LAKES, 



the sea, or that the part under water is about six sevenths of the 

 whole mass. 



The heights of several bergs were measured. Of all those at the 

 mouth of Jakobshavn, three exceeded 83 metres, the loftiest being 

 121 metres (according to several measurements with a theodolite), 

 the highest which I have ever seen. I estimate the quantity of ice 

 above the sea to have been 3,000,000 cubic metres, aud the whole 

 mass of the berg 21,000,000 cubic metres. The depth of Jakobshavn 

 Fjord, where the Greenlanders fish for halibut, is, judging from the 

 length of their lines, about 390 metres. From these numbers we 

 will endeavour to estimate the quantity of ice discharged through 

 the Jakobshavn Fjord. According to some measurements, the height 

 of the glacier above the sea, where it " calves," is about 40 metres. 

 Here, then, its whole thickness must be at least seven times the 

 above height ; for if it were floating, and so less thick, there would 

 be no " calving : " hence the thickness of the glacier must be here 

 at least 280 metres. Its mean rate of motion is 14*25 metres a 

 day. The breadth of the fjord is 4500 metres ; its sides slope at 

 angles of 20°, so its transverse section is a little more than 1,000,000 

 square metres. Hence the quantity of ice passing through this 

 daily in summer is about 16,000,000 cubic metres. In like manner 

 we find that the quantity of ice discharged by the Torsukatak 

 glacier is 6,300,000 cubic metres a day. 16,000,000 cubic metres 

 of ice represent what we may call a large berg ; so we see that the 

 daily discharge through the fjord of Jakobshavn, notwithstanding 

 the considerable velocity of the glacier, is only equal to one large 

 berg a day. This may, perhaps, surprise any one who has seen on 

 a summer's day the bergs passing in great numbers out of the 

 Jakobshavn Fjord ; but it must be remembered that all the bergs 

 produced during the long winter have to be removed during the 

 short space of summer. True, indeed, the rate of flow of the glacier 

 is probably diminished in winter, so that the quantity discharged 

 on a summer's day does not enable us directly to calculate that of 

 the whole year. If the rate of flow continued uniform, the Jakobs- 

 havn glacier would discharge annually 5,800,000,000 cubic metres ; 

 the Torsukatak glacier 2,300,000,000 cubic metres. It is not, how- 

 ever, probable that the quantity actually produced would be so little 

 as half of the above, for this would require the glacier to be 

 motionless during the three winter months. So we may estimate 

 the quantity of ice annually discharged from the Jakobshavn Fjord 

 to be between 2,900,000,000 and 5,800,000,000 cubic metres, 

 and that from the Torsukatak Fjord between 1,150,000,000 and 

 2,600,000,000 cubic metres. Calculating in like way the discharge 

 of the smaller fjords, as, for example, Alangordlek, we find that it 

 hardly produces one hundredth part of that from Jakobshavn. 



Large as are the quantities of ice thus yearly discharged from the 

 fjords, they form but a small fraction of the rain- and snowfall of 

 inner Greenland, the greater part of this passing away in rivers be- 

 neath the glaciers. Dr. Rink*, who estimates the ice yearly dis- 



* "Om Vandets Aflob fra det indre af Gronland," Naturhistorisk Tidsskrift, 

 3E.,i. B. 



