produced by the reflection and refraction of light again and again amongst these innumerable little crystals. Its color is blueish or greenish like a block of ice. A great quantity of air is entangled amongst the snow flakes, which makes snow such a good non-conductor of heat -nearly as good as a covering of feathers-preventing the earth losing its heat at night and so keeping the ground from freezing in cold weather. The actual fall of the temperature is 1 deg. for every 270ft. ascended. Thus, whatever the temperature of sea level, there is a certain height, where the air has an average temperature of 32 deg. F., or 0 deg. C. (freezing point). And no matter how much sun's heat passes through it, snow which falls above that height does not melt, and this is what is termed the "Snow Line." It is sea level in the Artic regions, about 5,000ft. in Norway, about 9,000ft. in Switzerland, and about 16,000ft. at the equator.

THE FORMATION OF A GLACIER.

There were certain geological mysteries which puzxled greatly the restless mind of the geologists, until the glacier and ice sheets presented a solution thereof. Huge stones and boulders, in great numbers and so many hundred of tons in weight, were found in spots far away from the rocks which by their constituents they were likely to have broken away from. And there was no known agency that could have transported these hugh and solitary stones to their present positions. Rocks and stones were noticed to be rounded, marked scored, rent, powdered by some unknown means. There were found layers of boulder clay, which those who work it tell us is even harder to work than the rock itself. All these facts were unexplainable till

the glacier and ice sheet came to the rescue and cleared these mysteries up. And now the botanist is telling us that the ice age is established by an examination of the different world's flora. The astronomers also, represented by Sir Robert Ball, tell us by exact and unmistakable astronomical calculations, that had not the geologist by his science established the facts of different ice ages, advancing and receding at long intervals over a large part of the present temperate parts of the world, they, the astronomers, would have said, to the geologist: "these ice ages are facts proved by our calculations. Go and look for the signs thereof over the world's crust."

As the snow falls and collects in the higher valleys of the high mountains, it gets gradually deeper and therefore heavier, till its weight is sufficient to press the underlying snow into the more solid form of ice, and thus the well known glacier comes into existence. Although ice is brittle it possesses many of the properties of a semi-fluid treacle. A small glacier can be made by placing a block of pitch at the uper end of a sloping board. In due time the pitch will gradually descend, and thus imitate the movement down a valley of an Alpine glacies. In these high regions under the great pressure of this constantly falling and never melting snow, the solid form of ice gets thicker and thicker, when the increasing pressure causes its slow movement from the mountain tops down the valleys. As the solid river winds its tardy way between the mountains, it has sufficient rigidity to do a tremendous amount of excavation, and so the icy river in the course of ages has formed deep ravines between the mountains. As it moves along its awful path of destruction and desolation, large bould

ers or stones, loosened it may be by the weather or other causes, fall on its surface and are thus carried along for miles and and miles from the place where they fell. Supposing now the climate slowly changes to a more genial warmth, the glacier will gradually melt, and eventually disappear, leaving as a relic of its course, these stones scattered here and there over the country. As this huge ice excavating maching moves along, it not only carries these fallen boulders called "Moraines," but it tears up huge pieces of rock from the rocky bed along which it is moving, and also scores and marks its channel by scratches and rude engravings paralled to the direction of its motion. Here we find projecting edges rounded off and sharp corners removed. At other places portions of the bed are smoothered and sometime even polifhed by the vigorous filing and rasping to which it has been subjected. In the Alps the speed of a glacier may be taken at 3ft. per diem, while in the Artic regions it is said to be about 90ft. In addition to these signs of the course of a glacier, the boulder clay is said to be formed be the awful weight and force of the moving glacier. The ice which lies. over the Antartic continent is said to several miles in thickness, and Dr. Nansen estimates that covering Greenland to average 2,090ft., and in some places 5 and 6,000ft. Let us take the low estimate of 1,000ft. in thickness. Every square inch of the ground over which this frozen ocean of 1,000ft. deep plunges its way would have to sustain a pressure of 400lbs. So every square foot of the country would bear a load of about thirty tons. This is double the pressure in the boiler of a locomoLet us try and imagine this huge engine of destruction slowly advancing; how it would rip up the

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rocks and earth, grinding and pulverising them all up inthe finest mud. The mud so created, in the case of an Alpine glacier, is removed by rapid and turbid rivers, which rush out from the termination of the glacier. But in a country overlaid by ice as Greenland, the mud is carried along by the advancing glacier and deposited in the power plains where these accumulations steadily grow, so that in the lapse of ages, a cushion of clay intermingled with stones is formed between the ice sheet and the solid rocks of earth's surface. The genial climate then comes round again, the glacier by melting shrinks back to the mountain valleys, and the soil of the low lying land lies bare once more to the great sun's warmth and power of life, but the mud is left behind, and becomes boulder clay, telling us unmistakably that here is the work of a glaicer.

ICE SHEETS AND THEIR EXTENT.

All these signs tell the geologist of many ice ages similar to that now existing over Greenland, which spread themselves over Scandinavia and choked up the North Sea; the greater part of the British isles-the southern part being spared; over the outlying islands of our Western coasts and for some distance into the Atlantic. The ice sheet seems to have extended from the North in central Europe. Over a great part of North America glaciers broad and deep submerged the Northern regions, and this more than once, for below the upper strata of boulder c'ay are found strata of soil containing specimens of plants and animals which could have existed only in a genial climate, and then below this again are found other strata of boulder clay. Sir Robert Ball states in a delightful little work called "The Cause of an Ice Age," that if the genial part of the earth

were to lose but 9 per cent. of the total heat it now receives from the sun, this loss would be sufficient to account for an ice age; and that at different periods parts of the earth have actually lost this amount owing to the pull of the planets, especially Jupiter and Venus, on the earth in its journey round the sun, which has had the effect of perturbing the earth in its course sufficiently to cause certain parts of the earth to lose 8 per cent. of heat. Sir Robert Ball states that when the Northern Hemisphere was in the glacial state, the Southern was genial, and when the Southern was in the glacial the Northern was in the genial. The interval of time between the extreme glacial period of the North and South is estimated at 10,500 years. Glacial periods thus succeed each other many times till a time comes when the earth has a measure of peace, such as we have now. This condition of things will last for thousands and thousands of years, and then again will come round fresh succeeding periods of glacial and genial. There is much more we could tell our readers of deep interest in connection with this science, but we have always exceeded our limits of space and commend to those enquirers "The wishing for more information Cause of an Ice Age," by Sir Robert Ball, and Dr. Nansen's "Crossing of Greenland:" the scientific results of the expedition found at the end of that work.

H. B. M. BUCHANAN, B.A.

A TRIBUTE TO THE MEMORY OF REV. T. CHARLES, BALA, N. W.

The following lines appeared in the Drysorfa thirty year ago. They were written by Thomas Ginfield, M. A. Clifton, and sent to the Rev. Thomas Phillips, secretary of the Bible Society on the occasion of the

space in the front of his home that made Watteau the first and greatest French painters of the eighteenth century; it was not working for his father as day-laborer or plowing horny stubble that made Burns the great poet of Scotland; nor was it the uncongenial train-labor which supported Edison during his early days that secured for him the title: "The Greatest Modern Inventor." Thousands have been brought up under the same circumstances as these celebrities, without one artist, or poet, as inventor arising from among them.

One

Furthermore, we have satisfying evidence in the large multitude of educated people, or college people as we sometimes call them,-who are utter failures, that education will not make one a true and successful man. And it is not the lives of illustrious personages and the failures of educated people, alone that maintain the verity of our assertion; for it will stand severe logical treatment and still remain unshaken. For instance, no two men see or think alike. man views an object differently from another, and yet both behold it with eyes of the same kind. Another man's thoughts upon a certain subject are contrary to his neighbor's; and a third will see beauty and grandeur in a moss-covered, tumble-down house, wood and stone. One man sees the necessity of fortyfying a certain position against the invading army and another sees that a strategic movement is expedient, while both, tho' by different methods, work for the ultimate good. This peculiarity in men is a divine distinction, bestowed, as far as we know, upon human beings