all natural phenomena are manifestations. We have a sketch, in ourselves, of the detail and plan which are worked up into the universal fabric: the lower anticipating the higher, and the higher fulfilling that anticipation.

The battle of life, therefore, through all time and in every field represents an unseen influence but visible in effect, taking away the feeble from an unequal contest, laying aside the lame if they cannot be made to walk, and carrying off the blind if they cannot be made to see; that the strong, the swift, the clear-sighted, may attain perfection. Butler's comparison may be true, that waste of seeds, like waste of souls, is a condition of psychic and organic progress; an analogue of selection carried out in the spiritual world. "Life is not a bully who swaggers out into the open universe, upsetting the laws of energy in all directions, but rather a consummate strategist, who, sitting in his secret chamber over his wires, directs the movements of a great army,' "1 and leads his forces to possess the worlds.

We pass now from Varieties in Life to the Manifold Changes of Inorganic Matter.

Chemistry is the science of experimental surprises. The most inert substances often producing, by combination, compounds of the strongest energy; the tasteless becoming intensely sour, sweet, or bitter; water, that quenches fire, containing the elements of fire; and the things which give and gladden life turning into demons of destruction. Many mineral, vegetable, and animal poisons, having apparently little in common, produce the same effect on the muscles as heat. The chemical union of different kinds of atoms, in the definite proportions of whole numbers, entirely changes their characters and properties. Two different liquids often condense into a solid; and the result of the chemical combination of two various gases or vapours, in quantitive proportions, may be solid, liquid, or aeriform. The ingredients of that acrid, dangerous, corrosive liquid, aquafortis, in different proportions, are constituents of the summer breeze. Another affinity of our atmosphere produces "laughing gas." More surprising, there are compound substances absolutely identi

"The Unseen Universe."

cal in the number and relative proportions of elements which in colour, odour, taste, are wholly unlike. The same substance will act as an acid in one combination, and as a base in another. Indeed, chemical laws seem imperfectly stated cases of some more general law of combination.

A piece of sugar falls into water, and sinks by law of gravity; but in a little while, it is found to have ascended and sweetened the whole. The same happens with salt, alum, and various other substances; yet, oil poured on the water will not diffuse itself through the mass; and gases of different densities put into a vessel will not, according to gravity, take different levels; but, by the law of diffusion, commingle.

Every different body requires a different quantity of heat to produce in it the same change of temperature; and the volume of most substances increases continuously as the temperature rises; but there is at least one exception among solid bodies-Iodide of Silver. The three principal states in which matter is found are the solid, the liquid, the gaseous; but most substances, probably all, are capable of existing in every one of these states; and the solid, passing into the liquid, is actually hotter than the liquid-the surplus heat is called latent. There is generally a change of bulk in the act of fusion; some expand, some diminish, we know not why. Ice dissolves into water of less bulk, but most substances enlarge. It requires more heat at high than low temperature to warm liquid one degree. Most liquids contract with cold, but water expands from 39° F. to 32° F., and then contracts. A glacier moves slowly on like a viscous body, an india-rubber band suddenly stretched out becomes warmer, if you pull out a steel spring it becomes colder. The conversion of liquid into vapour requires an amount of latent heat which is generally much greater than the latent heat of fusion of the same substance, and when a gas is near its point of condensation, its density increases more rapidly than the pressure. When it is at the point of condensation, the slightest increase of pressure condenses the whole into liquid, which seems contrary to the law-" the pressure of a gas is proportional to its density." In the liquid form the density increases very slowly

with the pressure. When temperature has attained a certain point, the properties of a liquid and those of the vapour continually approach to similarity, and above a certain temperature the properties of a liquid are not separated from those of a vapour by any apparent difference between them. Hence, the gaseous and liquid states are only widely separated forms of the same condition of matter, and pass into each other without any interruption or breach of continuity. In one way you can see this, in another you cannot. Begin, for example, with water take this path B, a, A; return by A, a, B. We begin with water at B, we have water and saturated steam about a, then superheated steam till we reach A. On our way back we have no such stages-though when we reach B there is water as at first.1

Potassium and sodium are somewhat remarkable: these metals are near akin in their specific gravities, their atomic weights, their chemical affinities, and the properties of their compounds. Potassium melts at 136°, sodium at 19°, but the alloy or mixture of the two is liquid at the ordinary temperature of the air. Cold is made to exist amidst hottest fire, and ice may be taken from a burning crucible. These are facts which only experiment could discover, and can only be reduced to law by a formula which includes both the usual course and the apparent exception. Observe more particularly as to water when in contact with ice it cannot be cooled below zero without being converted into ice. In heating the water the ice melts, but the temperature of the mixture is never raised above o° so long as the ice remains unmelted. Hence, the water contains a greater quantity of heat at o° than ice contains at o°, and gives up its heat to become ice. We do not know what becomes of this heat-nor how to account for the fact that water at o° is not ice, and that ice at o° is not water.

Physicists state that changes in consciousness are correlated with molecular motions of nerve matter, which are highly differentiated forms of solar radiance. Waves of this radiance speed to the earth at the rate of more than five hundred trillions to the second; and impart their energy so that we 1 "Recent Advances in Physical Science,” p. 335: Prof. P. G. Tait.

have growth of grass. Cattle browse on this, and hold in another form of equilibrium, by integration of tissues, these metamorphosed sunbeams. Man, assimilating the nitrogenous tissues of the cow, builds up that wonderful white and grey nerve-tissue by which is obtained the astonishing and completed transformation of solar radiance into human consciousness. We know of nothing more wonderful than this continual miracle: a miracle of progress by daily infinitesimal steps and transformations, and without our being able to say -"there is the place of birth." It is certain that a series of actions, displayed by the various tribes of the animal kingdom, may be so placed that they form one whole; of which it is impossible for the human intellect to resolve the complex into the more simple. That is not all: mental life comes out of physiological life, but how mental activity was originated in organisms by the simple elementary modifications of external to internal relations, and passed from the automatism of lowest creatures to the highest act of consciousness in man, is a mystery; nor can we say where intelligence begins, nor when

"turned the dense black element Into a crystal pathway for the sun.”

We can think of a world, all dark, beginning to vibrate differently and in various rapidities until all gorgeous colours shine in light and beauty; or we may conceive, as to the low rumblings of many motions requiring tone until every musical note vibrates in world-wide oratorio; so miraculous and varied is that operation by which, from things dark and silent, God brings the light of human intellect, and the many prayers and praises which make the earth a vast cathedral.

Of the innumerable combinations of matter and incarnations of energy which are going on all around us, we only know a few of the simplest; what then

"In yonder hundred million spheres ?"

Turn to the exactest of all sciences, Astronomy. What is revealed? The diamond dust in the sky becomes suns and stars. Little cloudlets expand and reveal worlds of majesty. There are variable suns, binary and multiple systems, stars suddenly blazing forth in splendour, and mys

Astronomical Varieties.

399

terious dark orbs rolling in night. Great is the variety of the stellar system; yet not a tithe of the various orders of bodies are known; we have only a faint conception of the wonderfully varied forms of creation within the stellar spaces. Not long ago, astronomers could scarcely allow that the vast depths, wherein the planets pursue their career, are the home of countless smaller bodies rushing in wide orbits round the solar mass. Few or none believed that those faintly gleaming lights, passing with silent swoop across a star group, leaving no trace of their existence and seeming of as little importance in the universe as a rain-drop or snow-flake, indicated the close of a career which had often, by uncounted millions of miles, surpassed the utmost limits of the known planetary system. These crowds of independent orbs, rushing disorderly round the sun, in no sort an obedient family, would, it was considered, make the sweet bells of the planetary system to jangle, be out of time, and harsh: nevertheless, the earth, sweeping on in her path, is exposed to cannonade from more than a hundred meteor systems; and at critical periods is assaulted with heavier metal than that encountered in the second week of November: not only balls weighing many pounds, but of several tons, have been shot against her.

How wonderful are the coloured suns! The brilliant Vega, a splendid steel-blue star, in the constellation Lyra, at midnight in winter, and earlier with the approach of spring, as it skirts the southern horizon, scintillates with red, blue, and emerald light. Arcturus, low down in the east and northeast, in spring evenings twinkles yet more beautifully. Capella, towards the north, in summer nights, notably sparkles. Sirius, noblest of all

"The fiery Sirius alters hue, And bickers into red and emerald."

These various colours are caused in part by our own atmosphere; but the stars are not wanting in real colours of their own. Sirius, Regulus, and Spica are white stars; Betelgeux, Aldebaran, Arcturus, and Antares are red; Procyon, Capella, and the Pole-star are yellow; Castor is of slightly green tint; Vega and Altair are bluish: Castor has a green companion, Antares also, and there is the well-known "garnet-star."