Dec. lo, 1885] 



NATURE 



127 



the water, became a great floating mass of ice in a week or less, 

 a mile in extent and of great thickness, and carried those good 

 explorers Weyprecht and Peyer helplessly about for a longtime 

 in 1873-74, in Barentz Sea, then landed them safe on one of the 

 Francis Joseph Islands ; thus leading to the discovery of this 

 great Northern land. Snowdrifts would in the course of one 

 winter (I have seen a fifteen feet depth of drift in one night) fill up 

 most of the inequalities of surface, and thus the floeberg is 

 complete. 



Lieut. Greely says that these "floebergs are simply detach- 

 ments from slowly-moving glacial ice-caps, from an ice-covered 

 land in the neighbourhood of the Pole;" that "Dr. Moss (of 

 the Alert) was certainly correct as to the universality of stratifi- 

 cation in this ancient ice, and he concurred in the Doctor's 

 opinion, that its salinity was due to efflorescence and infiltration. "' 



First as to the formation of these floebergs ; Lieut. Greely 

 tells us they are detached from an ice-cap 1000 to 4000 feet 

 thick near the Poles. Surely if this were so, some of these 

 great masses, which would show about 140 feet above water, 

 would have been seen by Parry, when in the summer of 1S27 he 

 was in lat. 82° 45' N. (only thirty-nine miles south of Greely's 

 extreme) to the north of Spitzbergen ; but neither Parry nor 

 any of the brave whaling captains, who have gone to high 

 latitudes between Greenland and Spitzbergen — the great high- 

 way of northern ice in its southward drift — have ever seen 

 anything of the kind. 



In the Antarctic we all know that such ice-mountains (the 

 source of which Sir James Ross's discoveries tell us of) drive 

 down to lat. 60° S. near to Cape Horn ; the natural idea is, that 

 they would do the same thing in the Arctic Sea — in company 

 with the great ice pack, through the wide high road above 

 mentioned — and not confine themselves to the coast seen by 

 Lieut. Greely's party. 



A word or two on my own experience much further to the south. 



When passing in my boats for 800 or 900 miles along the 

 west shores of Hudson's Bay in 1846 and 1853, I saw several 

 floebergs aground, some thirty or forty feet above the surface, so 

 large and high that any one at a distance of a mile or so, would 

 have mistaken them for true icebergs ; they were merely a mass 

 of floes forced together by strong winds. In such low latitudes 

 (58° to 66°) these spurious icebergs all disappeared before autumn. 



No (rue iceberg that breaks away from land-ice is ever found, 

 as far as I know, to contain saline strata, as the late Dr. Moss 

 found to be the case witli the floeberg from which the crew of 

 the Alert in 1875-76 took the ice, for drinking or making tea. 

 Sometimes this ice was so salt as to be unfit for the purpose, 

 although high above the sea- level. This resiUt is attributed by both 

 Dr. Moss and Lieut. Greely to "infiltration." I cannot under- 

 stand how saline fluid could "infiltrate" npiuctrds from the sea 

 into ice — a solid — in which there would be no pores through 

 which it could flow, apart from the fact of the greater specific 

 gravity of the brine. 



I do, however, know from personal experience that saline 

 fluid does, under certain circumstances, percolate or filtrate 

 dffiunwards, converting sea-ice, previously saline, into a suffi- 

 ciently fresh state to aftord good drinking-water when thawed. 

 This discovery, like a good many others of more importance, 

 was accidental. In passing a piece of old ice — that is, of a 

 former year's formation, which was known to be so by its 

 wasted and rugged outline, as it stood some feet above the sur- 

 rounding level ice-floe — I knocked a small piece ofi", and on 

 putting it into my mouth, found it quite fresh. From that time, 

 during sledge journeys of 1200 miles in the spring of 1847, I 

 looked out for some old rough ice, before building our snow- 

 hut for the night's shelter, so as to get water quickly. 



Experience had taught me that a kettleful of water could be 

 obtained much more rapidly and at a far less waste of fuel by 

 tliawing ice than from snow, because the latter, however closely 

 packed, contained much air, which, at a temperature of zero or 

 lower, required extra fuel to w arm it up to 32° Fahrenheit; a 

 kettleful of snow will give little more than a third of a kettleful 

 of water, whilst the same measure of ice will nearly fill the 

 kettle with water. 



The fresh ice I speak of could not be part of an iceberg, be- 

 cause there were no bergs in the great bay where we were 

 travelling. Moreover, if a piece of this ice (which was fresh at 



' I met the late Dr. Moss at the British Association when held some years 

 ago in Dublin. We conversed a good deal on the above subject. I learnt 

 from him, if my memory is correct, that the floeberg from which the crew of 

 the Alert took the ice to thaw for tlieir use, was found to have strata too 

 saline to drinli. This explanation 1 think requisite.— J. Rae. 



a few feet above the sea-line) was chopped off on a level with or 

 below the water-line, it was found to be saline. 



How does this take place ? Simply, I imagine, by the brine 

 or saline fluid filtrating downwards through pores made by itself 

 in the ice, as soon as the summer temperature became high 

 enough to thaw the saline part, the fresh portion retaining its 

 solidity, with the exception of the minute pores worn out as 

 above described. 



My belief is that the floebergs seen, and so named by the 

 English Expedition of 1875-76, were formed of saline sea-ice, piled 

 one floe over another, and that when the summer temperature 

 penetrated them to a certain extent, the salinity filtered down- 

 wards as above described, but that certain layers or strata, either 

 from not being subjected to a sufficient rise of temperature or 

 from some other cause, still retained their saltness. 



All sea-ice has a surface-layer, more or less thick, of brine 

 efflorescence, far more saline than the body of the floe. If, then, 

 six or eight floes are forced up, the one over the other, there 

 will be so many layers of these thin very saline strata. 



I repeat that infiltration upwards in this case is contrary to all 

 aws of gravit.ation, unless those learned in chemistry or physics 

 can show that there is some powerful attraction or affinity to 

 drag a saline fluid upwards through a dense solid. 



This communication has gone far beyond the limits I intended, 

 and yet is very short of what might be said on other parts of 

 Lieut. Greely's lectures in Scotland. I must conclude by ex- 

 pressing my admiration of the great amount of geographical 

 work done by this expedition, and the miraculous rescue of the 

 few survivors where twenty-four hours' delay would have been 

 fatal, resembling in this respect very closely the rescue of a 

 part of a Government overland expedition in Arctic America 

 sixty-four years years ago, who, but for the arrival of friendly 

 Indians with food and most tender musing of them, could not 

 have lived more than a couple of days longer. 



4, Addison Gardens, Kensington, Nov. 28 John Rae 



P.S. — The Scottish Geographical Magazine has just reached 

 me, by which I find Greely's mean temperature of his winter 

 quarters to be - 4° F. instead of + 4°, therefore almost exactly 

 the same as the temperature found by the English Expedition of 

 1875-76, instead of there being 8°difierence — as I put it. — J. R. 



December 7 



The Recent Star-Shower 



It being important to ascertain the duration of the recent 

 shower of Andromedes, observations were continued liere on 

 the night of November 30. During a watch maintained for 

 about four hours and a half between 5h. 30m. and loh. 15m,, 

 ten Andromedes of most certain character, together with two 

 other meteors, in reference to which some doubt existed as to 

 their absolute identity with this stream, were recorded from a 

 radiant-point carefully determined at 21^ + 424°. Thirty-one 

 non- con form able shooting-stars were also seen from showers in 

 Perseus and the region eastward. 



It is therefore clear, from the results obtained on November 

 30, that the display had not lost its visible character, though it 

 had evidently subsided into a state of great feebleness. It yielded 

 certainly not more than tliree meteors per hour for one observer, 

 and these were extremely faint. 



On the evening of December i the sky was again clear. A 

 prolonged watch of the region of Andromeda then revealed no 

 trace of the display. Meteors were very rare, generally, all the 

 evening. On December 4 they were very frequent, 'out the 

 radiant-point near 7 Andromedce gave no sign. The ^ I'auritls 

 and Geminids (which are specially mentioned in the current 

 number of Nature (p. loS) as deserving observation during 

 the present week) were both visible, and a number of contem- 

 porary streams had come actively into play. But, during long 

 watches on the nights of December I and 4, there was no ap- 

 pearance of outlying .'Vndromedes. The cessation of the shower 

 definitely occurred between November 30, lOh. 15m., and 

 December i, fh. 45m., after an ol)servcd iwxMorv of little more 

 than five days. But this period unquestionably fails to represent 

 the real duration, for, could observations have been made before 

 moonrise on the early evenings of November 24 and 25, tliere 

 is no doubt it would have been detected. We can hardly admit a 

 sudden rise of the shower from invisibility on the 25th to adegree 

 of richness on the 26th sufficient to give more than 100 meteors 

 per hour. It is to be hoped that reports from other stations will 

 throw some light on the visible development of this remarkable 

 stream. In any case the extremely narrow limits of its display 



