204 EJNAR MIKKELSEN. 
looking over the following table, which is a rough calculation of the 
decrease in the ice-belt, in square miles, between the different parallels. 
Average decrease of the pack-ice off the east coast of Greenland from 
67° N. Lat.—79°,N. Lat. in April, May, June, July & August. 
| | | Total decrease 
April— | May— | June— | July— in the quantity of 
May | June | July | August | ice from April— 
| August 
67°—68° М. Lat.... | 900 | 3,000 3,900 | 3,000 10,800 
GC yl 1,500 | 3,000 | 4,500 | 1,800 | 10,800 
69°—70° — ... | 1,500 3,600 | 4800 | 1,200 11,100 
Е ll 1,200 2,400 | 6,000 2,100 | 11,700 
(et At a SEE | 900 | 2,400 | 6,300 | 2,400 12,000 
12°—13° — ... 1,200 | 3,300 | 3,600 | 1,800 | 9,900 
73°—T4° — ... | 600 3,600 3,600 | 2,100 | 9,900 
(eB | 600 2,700 3,900 1,800 9,000 
0: 2,100 2400 | 1,800 | 6,600 
76°—11° — ... | 1,500 | 1,600 | 1,500 |: раб 4,000 
TCR | 1,000 | 0 300° | Эээ 5,200 
| 2400 | - 600 300 | 1,800 | 3,900 
10,000 | 27,700 | 41100 | 26,100 | 104900 
| | | | 
The decrease in the magnitude of the ice-belt pr. month is thus: 
From April to May 10% of total decrease from March—Sept. 
- May - June 26% - — - - - 
June July 359% - —- - - - 
- July - August 25% - -- - - - 
The reasons of this decrease are manifold, viz: 
less ice coming from the Polar Basin than what drifts away to 
the south; the influence on the ice-masses of the open ocean; 
the warmer currents flowing along the edge of the ice in three 
different places (branches of the Gulf-Stream); the melting 
caused by the warmer weather during the spring and summer 
and the decomposition of all thinner ice. 
The latter will probably be found to be the principal cause of the 
decrease, as all ice, which has been formed during the winter in the 
large ponds and openings between the older floes, is not very thick, 
has a salty surface, which accelerates the melting in an astonishing 
degree, and a strength considerably less than that of the surrounding 
older -ice. | 
SCORESBY jun. gives a very good description of the rapid decom- 
position of this kind of ice?) owing to the salt on its surface, which 
1 = denotes increase. 
* Account of the Arctic Regions. Vol. I, pag. 271. 
