of the object at which we have been looking still remains; or, when a spark is made to revolve rapidly, we think we see a circle of fire, the impression upon the retina lasting until the spark has completed its revolution. In like manner, though far more perfectly, are impressions registered or stored up in the sensory ganglia, the phantoms of realities that have once been seen. In those organs countless images may thus be superposed.

tween ani

Man agrees with animals thus approaching him in Analogies be- anatomical construction in many important respects. He, too, represents a continuous mals and man. succession of matter, a continuous expenditure of power. Impressions of external things are concealed in his sensory ganglia, to be presented for inspection in subsequent times, and to constitute motives of action. But he differs from them in this, that what was preparatory and rudimentary in them is complete and perfect in him. From the instrument of instinct there has been developed an instrument of intellection. In the most perfect quadrupeds, an external stimulus is required to start a train of thought, which then moves on in a determinate way, their actions indicating that, under the circumstances, they reason according to the same rules as man, drawing conclusions more or less correct from the facts offered to their notice. But, the instrument of intellection completed, it is quickly brought into use, and now results of the highest order appear. The succession of ideas is under control; new trains can be originated not only by external causes, but also by an interior, a spontaneous influence. The passive has become active. Animals remember, man alone recollects. Every thing demonstrates that the development and completion of this instrument of intellection has been followed by the superaddition of an agent or principle that can use it. There is, then, a difference between the brutes and man, not only as respects constitution, but also as tinction be- respects destiny. Their active force merges into other mundane forces and disappears, but the special principle given to him endures. We willingly persuade ourselves that this principle is actually personified, and that the shades of the dead resemble their

Points of dis

tween them.

living forms. To Eastern Asia, where philosophy has been accustomed to the abstract idea of force, the pleasures we derive from this contemplation are denied, the cheerless doctrine of Buddhism likening the life of man to the burning of a lamp, and death to its extinction. Perceiving in the mutation of things, as seen in the narrow range of human vision, a suggestion of the variations and distribution of power throughout nature, it rises to a grand, and, it must be added, an awful conception of the universe.

use.

But Europe, and also the Mohammedan nations of Asia, have not received with approbation that view. To them there is an individualized impersonation of the The human soul, and an expectation of its life hereafter. soul. The animal fabric is only an instrument for its The eye is the window through which that mysterious principle perceives: through the ear are brought to its attention articulate sounds and harmonies; by the other organs the sensible qualities of bodies are made known. From the silent chambers and winding labyrinths of the brain the veiled enchantress looks forth on the outer world, and holds the subservient body in an irresistible spell.

of the world.

This difference between the Oriental and European ideas respecting the nature of man reappears in their Extension of ideas respecting the nature of the world. The these views one sees in it only a gigantic engine, in which to the nature stars and orbs are diffusing power and running through predestined mutations. The other, with better philosophy and a higher science, asserts a personal God, who considers and orders events in a vast panorama before him.

CHAPTER XI.

THE EUROPEAN AGE OF REASON-(Continued).

THE UNION OF SCIENCE AND INDUSTRY.

European Progress in the Acquisition of exact Knowledge.—Its Resem blance to that of Greece.

Discoveries respecting the Air-Its mechanical and chemical Properties -Its Relation to Animals and Plants.-The Winds.-Meteorology.— Sounds.-Acoustic Phenomena

Discoveries respecting the Ocean-Physical and chemical Phenomena.-Tides and Currents.-Clouds-Decomposition of Water. Discoveries respecting other material Substances.-Progress of Chemistry. Discoveries respecting Electricity. Magnetism, Light, Heat Mechanical Philosophy and Inventions-Physical Instruments.—The Result illustrated by the Cotton Manufacture—Steam-engine—Bleaching-Canals Railways.-Improvements in the Construction of Machinery. Social Changes produced.—Its Effect on intellectual Activity. The scientific Contributions of various Nations, and especially of Italy. THE Age of Reason in Europe presents all the peculiarities of the Age of Reason in Greece. There are modern representatives of King Ptolemy Philadelphus among his furnaces and crucibles; of Hipparchus cataloguing the stars; of Aristyllus and Timochares, with their stone quadrants and armils, ascertaining the planetary motions; of Eratosthenes measuring the size of the earth; of Herophilus dissecting the human body; of Archimedes settling the laws of mechanics and hydrostatics; of Manetho collating the annals of the old dynasties of Egypt; of Euclid and Apollonius improving mathematics. There Analogies be- are botanical gardens and zoological menageries tween the Age like those of Alexandria, and expeditions to the Europe and in sources of the Nile. The direction of thought is Greece. the same; but the progress is on a greater scale, and illustrated by more imposing results. The exploring

of Reason in

voyages to Madagascar are replaced by circumnavigations of the world; the revolving steam-engine of Hero by the double-acting engine of Watt; the great galley of Ptolemy, with its many banks of rowers, by the ocean steam-ship; the solitary watch-fire on the Pharos by a thousand lighthouses, with their fixed and revolving lights; the courier on his Arab horse by the locomotive and electric telegraph; the scriptorium in the Serapion, with its shelves of papyrus, by countless printing-presses; the "Almagest" of Ptolemy by the "Principia" of Newton; and the Museum itself by English, French, Italian, German, Dutch, and Russian philosophical societies, universities, colleges, and other institutions of learning.

So grand is the scale on which this cultivation of science has been resumed, so many are those European engaged in it, so rapid is the advance, and so progress in the acquisigreat are the material advantages, that there is tion of knowno difficulty in appreciating the age of which it ledge. is the characteristic. The most superficial outline enables us to recognize at once its resemblance to that period of Greek life to which I have referred. To bring its features into relief, I shall devote a few pages to a cursory review of the progress of some of the departments of science, selecting for the purpose topics of general interest.

First, then, as respects the atmosphere, and the phenomena connected with it.

From observations on the twilight, the elasticity of aerial bodies, and the condensing action of cold, The atmothe conclusion previously arrived at by Alhazen sphere. was established, that the atmosphere does not extend unlimitedly into space. Its height is considered to be about forty-five miles. From its compressibility, the greater part of it is within a much smaller limit; were it of uniform density, it would not extend more than 29,000 feet. Hence, comparing it with the dimensions of the earth, it is an insignificant aerial shell, in thickness not the eightieth part of the distance to the earth's centre, and its immensity altogether an illusion. It bears about the same proportion to the earth that the down upon a peach bears to the peach itself.

A foundation for the mechanical theory of the atmo

sphere was laid as soon as just ideas respecting liquid pressures, as formerly taught by Archimedes, were restored, the conditions of vertical and oblique pressures investigated, the demonstration of equality of pressures in all directions given, and the proof furnished that the force of a liquid on the bottom of a vessel may be very much . greater than its weight.

Coinci

Such of these conclusions as were applicable were soon Its mechani- transferred to the case of aerial bodies. The cal relations. weight of the atmosphere was demonstrated, its pressure illustrated and measured; then came the dispute about the action of pumps, and the overthrow of the Aristotelian doctrine of the horror of a vacuum. dently occurred the invention of the barometer, and the proof of its true theory, both on a steeple in Paris and on à mountain in Auvergne. The invention of the air-pump, and its beautiful illustrations of the properties of the atmosphere, extended in a singular manner the taste for natural philosophy.

The mechanics of the air was soon followed by its cheIts chemical mistry. From remote ages it had been numrelations. bered among the elements, though considered liable to vitiation or foulness. The great discovery of oxygen gas placed its chemical relations in their proper position. One after another, other gases, both simple and compound, were discovered. Then it was recognized that the atmosphere is the common receptacle for all gases and vapours, and the problem whether, in the course of ages, it has ever undergone change in its constitution arose for solution. The negative determination of that problem, so far as a few thousand years are concerned, was necessarily followed by a recognition of the antagonism of animals and plants, and their mutually balancing each other, the latter accomplishing their duty under the influence of the sun, though he is a hundred millions of miles distant. From this it appeared that it is not by incessant interventions that the sum total of animal life is adjusted to that of vegetable, but that, in this respect, the system of government of the world is by the operation of natural causes and law, a conclusion the more imposing since it contemplates all living things, and

The antagonism of animals and plants.