Nordenskjöld gives some very interesting details about this dust, from observations made during his various expeditions. At one time it was supposed to be a slimy mass carried down from the hills which pierce the snow, and lodged on the lower stretches of its upper surface; but Nordenskjöld found this same dust in like quantity on the interior ice-fields of Greenland, where for miles around there were no mountains near, and also on ice-hummocks that quite surmounted the ice-plains, as well as on the nearest hills. During their long sojourn in the land of ice, they searched very carefully for any traces of small stones even as large as a pin’s head; but they could find none; while many square miles were covered by this fine dust, gray in its dry state, and becoming black when moist. It was therefore at last decided that this dark-coloured matter must be a precipitate from the atmosphere, and that the summer sun melting the snows, had allowed numerous dust-showers to accumulate thus, one on the top of the other. Nordenskjöld further thinks that it is not exclusively earth-dust wafted thither by currents of air, but that it contains a number of metallic particles, that can be extracted by a magnet, consisting, like the metallic meteor-stones, of iron, nickel, and cobalt. This metallic cosmic dust, which has been noticed previously in our pages, and which is spread over the whole world, is best observed and gathered on these vast snow and ice fields, and as it also bears a similitude to our ordinary earth-dust, Nordenskjöld has given it the name of Kyrokonit, or ice-dust.
At first, the alga of the red snow was looked upon as the sole inhabitant of the ice-lands of the polar regions; but in 1870, Dr Berggren, botanist of Nordenskjöld’s expedition, discovered a second or reddish-brown alga. It is allied to the ‘snow-blossom,’ but has this peculiarity, that it is never found on snow, but combined with the kyrokonit, it covers enormous tracts of ice, giving to them a beautiful purple brown tint, which greatly adds to their beauty. Besides growing on the surface of the ice, this red-brown alga was also found in holes one or two feet deep, and three or four feet across, in some parts so numerous and close together that there was scarcely standing-room between them. A closer examination showed that this very alga was the cause of these holes, as wherever it spreads itself, it favours the melting of the ice. The dark-brown body absorbs more heat than either the gray dust or the snow, therefore it sinks ever deeper into the hollows, until the slanting rays of the sun can no longer reach it.
Thus these microscopic algæ play the same part on the ice-fields of Greenland that small stones do on European glaciers. By creating holes, they give the warm summer air a larger surface to take hold of, and thus materially assist the melting of the ice. Perhaps it is to these microscopic atoms that we owe some of the vast changes that our globe has experienced; it may be by their agency that the vast wastes of snow that in the glacial period covered great tracts both of the European and American continents for some distance from the poles, have melted gradually away and given place to shady woods and fields of grain. It is indeed a remarkable instance of the power and importance of even the smallest thing in nature; all the more interesting in this case, that the sun creates for itself in these tiny dark atoms, the instruments for boring through the ice.
One important fact we must not forget to mention in conclusion, namely, that these microscopic plants have tempted many insects—to which they serve as food—into these inhospitable regions. A small black glacier flea lives principally on the red snow; and even in the arctic regions we find many tiny insects subsisting entirely on the red and green algæ. These insects, too, possess the same property as the algæ, of shutting themselves up in capsules during the long winter, and like them too, remain alive even when in a dried condition. When Professor Wittrock, in the winter of 1880 to 1881, placed the dried spores of the red snow in water to germinate, a number of tiny colourless worms appeared, still living. Thus even the stern, rigid north pole cannot prevent the universal spread of life; and if those cosmological prophets are right who declare that the whole surface of the earth will one day be covered with snow and ice, then these minute insects will have an ample store of food in the red, green, and brown algæ, and as the last of living beings, will be able to mock at the general stagnation; ay, perhaps even become the foundation of a fresh development of life on our earth, should any cosmical cause sufficiently increase the temperature.
OCCASIONAL NOTES.
EXTENDED USE OF GAS COOKING-STOVES.
We have repeatedly called attention to the practical utility and convenience of gas-stoves for cooking purposes, and facts to hand seem to show that these are being largely taken advantage of by the public. Many gas Companies now lend them out at a cheap rate, and they may be had for purchase at a price to suit most buyers. Since the Corporation Gas Company of Glasgow introduced the system of hiring out these stoves, about three thousand five hundred had been lent out in six months, and the demand continues unabated. In hotels, restaurants, and many a private home, they are found doing their work with economy, ease, and a great saving of labour.
Dr Stevenson Macadam, speaking of gas-cooking in its sanitary aspects, says: ‘The wholesomeness of the meat cooked in the gas-stoves must be regarded as beyond doubt; gas-cooked meat will be found to be more juicy and palatable, and yet free from those alkaloidal bodies produced during the confined cooking of meat, which are more or less hurtful, and even poisonous.’ A joint cooked in a gas-oven weighs heavier than the same joint cooked in a coal-oven, from the fact, that in the case of the gas-cooked joint the juices are more perfectly preserved.
At the East London Hospital, where the entire cooking for an enormous number of patients is done by gas, the managers calculate that fully six hundred pounds is saved yearly since the introduction of gas-cooking.
For the extended use of gas-stoves in Scotland, the public is greatly indebted to R. and A. Main, Glasgow, who are ever ready to adopt everything new in gas-apparatus. Gas is also now largely used in connection with washing by means of steam. When we noticed Morton’s Steam-washer, probably not more than half a dozen had adopted this easy and economical method of washing, in Scotland, and now those who do so may be counted by the hundred.