pretation of Nature, if accuracy of vision be thereby impaired. But the term Vorstellungs-fähigkeit, as used by me, means the power of definite mental presentation, of attaching to words the corresponding objects of thought, and of seeing these in their proper relations, without the interior haze and soft penumbral borders, which the theologian loves. To this mode of "interpreting Nature" I shall to the best of my ability now adhere.
Neither of us, I trust, will be afraid or ashamed to begin at the alphabet of this question. Our first effort must be to understand each other, and this mutual understanding can only be insured by beginning low down. Physically speaking, however, we need not go below the sea-level. Let us, then, travel in company to the Caribbean Sea, and halt upon the heated water. What is that sea, and what is the sun which heats it? Answering for myself, I say that they are both matter. I fill a glass with the sea-water and expose it on the deck of the vessel; after some time the liquid has all disappeared, and left a solid residue of salts in the glass behind. We have mobility, invisibility—apparent annihilation. In virtue of
"The glad and secret aid
The sun unto the ocean paid,"
the water has taken to itself wings and flown off as vapor. From the whole surface of the Caribbean Sea such vapor is rising; and now we must follow it—not upon our legs, however, nor in a ship, nor even in a balloon, but by the mind's eye—in other words, by that power of Vorstellung which Mr. Martineau knows so well, and which he so justly scorns when it indulges in loose practices.
Compounding, then, the northward motion of the vapor with the earth's axial rotation, we track our fugitive through the higher atmospheric regions, obliquely across the Atlantic Ocean to Western Europe, and on to our familiar Alps. Here another wonderful metamorphosis occurs. Floating on the cold, calm air, and in presence of the cold firmament, the vapor condenses, not only to particles of water, but to particles of crystalline water. These coalesce to stars of snow, and afterward fall upon the mountains In forms so exquisite that, when first seen, they never fail to excite rapture. As to beauty, indeed, they put the work of the lapidary to shame, while as to accuracy they render concrete the abstractions of the geometer. Are these crystals "matter?" Without presuming to dogmatize, I answer for myself in the affirmative.
Still, a formative power has obviously here come into play which did not manifest itself in either the liquid or the vapor. The question now is, Was not the power "potential" in both of them, requiring only the proper conditions of temperature to bring it into action? Again I answer for myself in the affirmative. I am, however, quite willing to discuss with Mr. Martineau the alternative hypothesis, that
