duced living larvæ. All the Myriapods respire by agency of trachea, but Sir John Lubbock describes a curious little myriapod, Pauropus, which has a look of cheerful intelligence, no trachea, and respires, he supposes, through the skin. All these varieties, of which natural uniformity is the theatre for display, are indications of a mysterious energy working in particular ways, adjusting inner and outer relations; and, however elevated and complicated the result, it is wrought by means of the simplest elements, and generally by insensible degrees. The smallest amount of intelligence requires perfect organisation but mechanical appliances, implements, tools, necessary to produce good work, do not convey intelligence, though they may be called its mechanical basis. Nature seems to have a purpose in everything, and works as knowing how to do it, though the purposeless or "silent members" in animal. frames are hard to account for. Some animals have teeth, never meant to eat with; the rudiments of toes in a horse, and teats in male animals, are utterly useless. Are we thence to infer that eyes are not meant to see with; nor feet to walk with; nor teeth to eat with; nor was "a duck expressly intended to be a duck with a web-foot, that it might pleasantly move on the water; but forefathers and mothers a long way back began, under pressing circumstances, to get a duckish disposition; and by dint of endeavour for ages to try their chance of paddling themselves about on the pools of a puddly world, were at length rewarded with complete success-so remarkable indeed, that a generation sprang from them. thoroughly equipped for the waters with web-feet, oily back, boat-shaped bodies, spoony bills, and bowels to correspond with mudworms and duckweed?" Surely it is time to lay aside notions so grotesque, and to live, as did Newton and Boyle, in the conception that "God dwells within, and moves the world and moulds, Goethe. If not able to assign a purpose for these purposeless struc "The First Man and His Place in Creation," p. 36: George Moore, M.D. Rudimentary Organs. 419 tures, we are less able to account for them as a natural selection they would be unnatural. It is inconceivable that any creature could or would voluntarily grow them; nor can we credit that any brute is able to make an intelligent attempt, by means of purposeless structures, to become intelligent. It is incredible that any animal would put swiftness from the feet, fangs from the mouth, claws from the paws, cast aside the acute sense of smell, in order to advance in life; or that any intelligent creature would divest itself of those advantages. As for time and space, they are not structural causes, and could never enable any brute to generate a progeny that would submit to conditions of moral responsibility. If, however, we consider that "silent members" were of use in the past, or are for use in the future; that there is in Nature an agency of use and disuse; light begins to shine in the darkness. Rudimentary organs then show somewhat of the stages by which old forms die out and new forms come in : by modifications acting through generations of ancestral organisms. If not, there is another explanation:-The finished and complicated parts of our most wonderful machinery are all found typified in simpler shape, and narrower use in smaller or in primitive engines: so the imperfect organs of lower animals become perfect in higher creatures. In like manner, the human mind is a real though faint emblem of the Wisdom of which 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, the higher fulfilling that anticipation. The battle of life 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, carrying off the blind if they cannot be made to see; that the strong, the swift, the clearsighted, may attain perfection. Butler's comparison may be true; 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," and leads his forces to possess the world. We pass from Varieties in Life to the Manifold Changes of Inorganic Matter. Chemistry is the science of experimental surprises. The most inert substances often produce, by combination, compounds of the strongest energy; the tasteless becoming intensely sour, sweet, or bitter; water, that quenches fire, contains the elements of fire; and things which give and gladden life turn into demons of destruction. Many mineral, vegetable, 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. Paint is made which so absorbs and retains bright light as to become luminous in the dark. 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 identical 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, sinks by law of gravity; but, in a little while, is found to have pervaded 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 take different levels according to gravity, but commingle, by the law of diffusion. 1 "The Unseen Universe." 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. The solid, passing into the liquid state, is actually hotter than the liquid-the surplus heat, used up in liquefying, is called latent. There is generally a change of bulk in the act of fusion; some substances expand, some diminish, we know not why. Ice dissolves into water of less bulk, but most substances enlarge by liquefaction. 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 crystallizes. A glacier moves slowly on like a viscous body, although ice is not viscous. An indiarubber 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, 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 different 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. M. Daubrée, by heating water to a very high temperature, and under pressure in strong glass tubes, has produced silica in a crystallised condition similar to the crystals of quartz. There is now a process for the production of carbon in the state of crystals. The products do not seem to be diamonds, nor is the crystalline substance truly carbon; but, possibly, diamond dust may be manufactured, and ultimately diamonds of magnitude. Industrious workers are pushing investigation and experiment into every field, are adding to our knowledge year by year, and increasing our power to use the forces of Nature for our own purposes. 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 fuses at 144'5° F., sodium at 207.7° F., 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 discovers, and can only be reduced to law by a formula which includes 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 32° F. so long as the ice remains unmelted. Hence, the water contains a greater quantity of heat at 32° F., than ice contains at 32° F., and gives up or uses its heat in the effort to become ice. Physicists state that changes in consciousness are correlated with molecular motions of nerve-matter, which are highly differentiated forms of solar radiance. They mean-vital energy differentiates the waves of solar radiance into those undulatory motions of nerve-matter which excite organic consciousness. 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 have growth of grass. Cattle browse on this, and hold in another form of equi 1 "Recent Advances in Physical Science," p. 335: Prof. P. G. Tait, M.A. |