324 



SCIENCE. 



[Vol. IX., No. 317 



The foregoing table shows the extent of the 

 Pacific-Arctic fishery from 1877 to 1886. The 

 number of whales secured each year varies greatly. 

 In 1880, 365 were caught ; in 1885, 833 ; and in 1886, 

 only 153. The ' whale ' oil includes also oil of 

 walrus. 



A. Howard Clark. 



ICE AND ICEBERGS. 



In a paper read before the Eoyal society of Can- 

 ada (May 37, 1886), ' On some points in reference to 

 ice phenomena,' Dr. Robert Bell discusses various 

 observations on the formation of ice and its action 

 on the land. The rapid disappearance of icebergs 

 after they have passed the banks of Newfound- 

 land, he ascribes to the difference in temperature 

 of the Gulf Stream and the interior of the berg, 

 which is probably much colder than 0° C. He 

 supposes that the rapid increase of the tempera- 

 ture of the water causes the ice to crack ; and this 

 process, once started, would rapidly continue as 

 the colder parts of the interior come in contact 

 with the water. An experiment made at Ottawa 

 proved that ice, on coming in contact with warm 

 water, really cracks. Though the difference in 

 temperature may take an active part in fracturing 

 icebergs, some other facts ought to be investigated 

 before it is possible to decide on this question. The 

 icebergs of the Labrador current show, even while 

 in BaflSn Bay, many signs of decay. The most re- 

 markable ones are the de^p grooves hollowed out 

 by the waves breaking at the foot of the icy cliffs. 

 The depth of these excavations and the amount of 

 debris scattered around the berg prove the efficacy 

 of the waves in breaking up the berg. However, 

 the greater part of the year the bergs are embed- 

 ded in pack-ice, and protected from the action of 

 the swell. This continues as far as the Labrador 



coast. As soon as the berg reaches the southern 

 end of the pack-ice, the breakers formed by the 

 Atlantic swell will undermine its cliffs, the debris 

 furthering their action. The history of icebergs 

 may well be observed in Baffin Bay. The greater 

 number are flat, and shaped like a table, having a 

 flat top and vertical edges. They attain a size of 

 from twenty-five to thirty square miles, and are 

 about four hundred feet thick, their height above 

 the water being fifty feet. These masses of 

 ice, on striking a rock or a shoal, are broken up 

 into small pieces, all of which have vertical 

 edges. A very few of these are tilted, the hori- 

 zontal top becoming inclined and partially sub- 

 merged. Thus some parts of the berg attain a far 

 greater height than they had before the tilting, 

 and it is probably thus that the high and pointed 

 icebergs originate. Flat bergs are very stable, 

 while pointed ones show signs of frequent tilting 

 and capsizing. Grooves which were excavated by 

 the swell may be seen in all parts of the berg, 

 some of them even running vertically. Some- 

 times many parallel grooves prove that large pieces 

 of the unsubmerged part of the berg broke off, 

 and that it gradually emerged from the ocean. 

 Grooves diverging from one edge are of frequent 

 occurrence, and were caused by the lifting of one 

 side of the berg. It would be of great importance 

 to know whether the tilting has any influence upon 

 the direction of the cracks and fissures. These 

 are always vertical while the bergs are in their 

 original position. There are no observations which 

 would enable us to decide whether the same direc- 

 tion is maintained after the tilting, which would 

 be of eminent influence on the breaking-up of 

 the iceberg. If, after the tilting has occurred, in- 

 clined faces would originate, this would materially 

 contribute to a rapid destruction. As even small 

 pieces of the large bergs have vertical edges, their 

 direction is probably due to the structure of the 

 ice, and wiU be maintained in any position the ice 

 may have. 



Bell remarks that the amount of rocky and 

 earthy material carried from north to south by 

 bergs is not very large. Field-ice, on the other 

 hand, particularly such as is formed in shallow 

 bays with high tides, and near the land, always 

 carries great quantities of mud and stones, which 

 are carried upon it by the wind or avalanches. 

 We do not think that any amount of material is 

 carried upon the ice by torrents formed by the 

 melting of snow, as Bell supposes. The ice always 

 contains some salt, and, as the melting-point of 

 the fresh water coming from the land is higher 

 than that of the ice, the latter is rapidly wasting 

 at the mouths of the rivers. 

 In regard to the formation of Frazil (anchor) ice, 



