Science has developed methods and implements of incredible delicacy.  Its “microbalance” can estimate “the difference of weight of the order of the millionth of a milligram.”  Light travels at the speed of 186,000 miles a second, yet science can follow it with its methods, and finds that it travels faster with the current of running water than against it.  Science has perfected a thermal instrument by which it can detect the heat of a lighted candle six miles away, and the warmth of the human face several miles distant.  It has devised a method by which it can count the particles in the alpha rays of radium that move at a velocity of twenty thousand kilometers a second, and a method by which, through the use of a screen of zinc-sulphide, it can see the flashes produced by the alpha atoms when they strike this screen.  It weighs and counts and calculates the motions of particles of matter so infinitely small that only the imagination can grasp them.  Its theories require it to treat the ultimate particles into which it resolves matter, and which are so small that they are no longer divisible, as if they were solid bodies with weight and form, with centre and circumference, colliding with one another like billiard-balls, or like cosmic bodies in the depths of space, striking one another squarely, and, for aught I know, each going through another, or else grazing one another and glancing off.  To particles of matter so small that they can no longer be divided or made smaller, the impossible feat of each going through the centre of another, or of each enveloping the other, might be affirmed of them without adding to their unthinkableness.  The theory is that if we divide a molecule of water the parts are no longer water, but atoms of hydrogen and oxygen—­real bodies with weight and form, and storehouses of energy, but no longer divisible.

Indeed, the atomic theory of matter leads us into a non-material world, or a world the inverse of the solid, three-dimensioned world that our senses reveal to us, or to matter in a fourth estate.  We know solids and fluids and gases; but emanations which are neither we know only as we know spirits and ghosts—­by dreams or hearsay.  Yet this fourth or ethereal estate of matter seems to be the final, real, and fundamental condition.

How it differs from spirit is not easy to define.  The beta ray of radium will penetrate solid iron a foot thick, a feat that would give a spirit pause.  The ether of space, which science is coming more and more to look upon as the mother-stuff of all things, has many of the attributes of Deity.  It is omnipresent and all-powerful.  Neither time nor space has dominion over it.  It is the one immutable and immeasurable thing in the universe.  From it all things arise and to it they return.  It is everywhere and nowhere.  It has none of the finite properties of matter—­neither parts, form, nor dimension; neither density nor tenuity; it cannot be compressed nor expanded nor moved; it has no inertia nor mass,