The thought which will occur to most people, in dealing with the fact of glacial motion, is, that the weight of the ice will give the glacier a direction toward the valleys below. This is the Gravitation Theory of De Saussure, who first stated it in exact language, and added to it the alleged likelihood, that the downward motion would be helped by the water believed to be flowing underneath the glacier. Charpentier, Agassiz, and others, substituted another hypothesis-that of Dilatation. They held that "the pores in the ice being filled with water during the day, this water expanded in freezing, and propelled the glacier in the direction of least resistance—that is, down the valley." Both of these theories have been carefully examined by Professor James Forbes; and while he has admitted that they explain some facts connected with glacier movement, he has shewn that they cannot account for the leading phenomena. Examining the gravitation hypothesis of De Saussure, he admits that subterranean heat may influence the glacial mass in detaching it from its bed; but he shews that the seasons would modify this, and so make the motion of the glacier neither definite nor continuous. The Dilatation Theory of Charpentier and Agassiz would, among other things, imply that when there was no thaw there would be no motion; but this was found not to be the case, as the motion was proved, by a number of beautiful and interesting experiments made by Professor Forbes, to be the same during the day as during the night. The new, and, as it seems to us, perfectly satisfactory theory is this:-"A glacier is an imperfect fluid, or a viscous body, which is urged down slopes of a certain inclination by the mutual pressure of its parts." The fact of the motion and the manner of it was beautifully illustrated by the experiments of the Edinburgh Professor. He put a number of marks into the ice in a straight line, and found that they gradually assumed the form of a curve, the middle part pointing down the valley. This result shewed that the laws of glacier motion are much the same as those which regulate the course of rivers, whose progress is known to be more rapid at the centre than at the sides, and faster at the top than at the bottom. We can easily imagine what must have been the interest with which these experiments were conducted among those awful Alpine solitudes, and can enter into those deep feelings which are brought out in the thoughtful and chastely beautiful sentences which conclude the “Travels through the Alps of Savoy:" "Poets and philosophers have delighted to compare the course of human life to that of a river; perhaps a still apter simile might be formed in the history of a glacier. Heaven-descended in its origin, it yet takes its mould and conformation from the hidden womb of the mountains which brought it forth. At first soft and ductile, it acquires a character and firmness of its own, as an inevitable destiny urges it on its onward career. Jostled and constrained by the crosses and inequalities of its prescribed path, hedged in by impassable barriers which fix limits to its movements, it yields groaning to its fate, and still travels forward seamed with the scars of many a conflict with opposing obstacles. All this while, although wasting, it is renewed by an unseen power-it evaporates, but is not consumed. On its surface, it bears the spoils which during the progress of existence it has made its own;—often weighty burdens devoid of beauty or value— at times precious masses, sparkling with gems or with ore. Having at length attained its greatest width and extension, commanding admiration by its beauty and power, waste predominates over supply, the vital springs begin to fail; it stoops into an attitude of decrepitude; it drops the burdens, one by one, which it had borne so proudly aloft--its dissolution is inevitable. But as it is resolved into its elements, it takes, all at once, a new and livelier and disembarrassed form; from the wreck of its members it arises "another, yet the same," a noble, full-bodied, arrowy stream, which leaps rejoicing over the obstacles which before had stayed its progress, and hastens through fertile valleys towards a freer existence, and a final union in the ocean with the boundless and the infinite." CHEMISTS AND CROPS. Two things are true of the glowing descriptions, given by some of the Greek and Roman classical writers, of the "golden age." The one is, that the time when the earth laughed with abundance, and brought forth spontaneously all that was needed for the sustenance of man and beast, lies, to us, far back in the past; and the other is, that the full ushering in of that good time to which the religious instincts, even of the heathen, looked forward, and which we, too, by the grace of God, are permitted to expect, lies, as yet, in the shadowy future. Meanwhile, our lot is cast in another age than the rich natural abundance of the golden one, and the question for us all will, while we so live, come to be, how shall we make the best of that earth which God has given to the children of men? From the soil man draws that which sustains his body, but, before the reluctant earth will yield even that, it needs to be dealt with-subjected to the various processes necessarily implied before the corn can be made ours in order to bread, and the green herb ours in abundance in order to the support of the beasts which form a staple article in the food of man. This unwillingness of the earth to yield us abundance is felt by all. Men who may not receive the Word of God as that which alone lets true light in upon the present condition of the earth, acknowledge that it bears on it multiform evils, and often fails in supplying the " mean inhabitant" with all that he needs, and they sing of, and long for, "the good time coming;" or, under the reflex influence of this same Word, thus as to its true utterances ignored, they have come to feel something like the power of the "good hope" itself. Thus a leader of this party cries Oh, that the Son Might come again! There should be no more war, No more want, no more sickness; with a touch, He would cure all disease, and with a word, All sin; and with a look to heaven, a prayer, Every one who has sat at the feet of Jesus, and heard His Word, receives the testimony of the Spirit, that “the earnest expectation of the creature waiteth for the manifestation of the sons of God." And again, "For we know that the whole creation groaneth and travaileth in pain until now." In hope they look for Him, at whose appearing they will be introduced into that plenty which prophets and men of God have from the beginning loved to anticipate. Now, we are not to sit down in idleness and merely wait for this time. We are to work, till it please the Father to introduce it; and in this we meet with the goodness of God. He blesses man's efforts in trying to neutralise the thistly curse, and so deals with the efforts of men and the triumphs of science as to convince us, that every improvement coincides with His purposes concerning the earth. On this we can rest two thoughts, namely, 1st, That we are working out God's plans in labouring to reduce more and more the curse which is on the ground; and, 2d, That, with all our improvements, we are not less dependent upon Him than we were when the cultivation of the ground had little else applied to it than the spade of the husbandman. Having taught the husbandman discretion, it is God's wish that he should apply it to the best advantage. But He reserves in His own hand the sovereign control in granting or withholding the blessing. Thus, while the use of means is expected to lead to a certain result, no man can infallibly count on success. A plentiful harvest comes thus to be as truly the gift of God, after man has put all his appliances forth in order to it, as it would have been had man done nothing in it at all. We need to keep this in view, because the progress in science, the triumphs of man over the ele |