And yet it is when we come to study the dimensions of this operation in detail, that the sense of its vastness grows upon us and overpowers us. David never could have felt, as we can feel, the force of his own words: When I consider thy heavens, the work of thy fingers, The moon and the stars which thou hast ordained, What is man that thou art mindful of him, And the son of man that thou visitest him! They are like the chariot of Ezekiel's vision, "so high that it was dreadful." It seems a fearful thing to have to do with such magnitudes; and when we hear of scholars in their observatories measuring the distances among the stars, it overcomes us with a giddy feeling, as when we see men clambering on church spires, or crossing the East River on a strand of wire. A row of figures on a slate does seem such a frail support on which to go marching through the starry spaces! We almost shudder when we see human science springing clear of the narrow boundaries of the earth, and on such attenuated threads of calculation venturing boldly forth to other planets, and thence over chasms of space so vast that it is easiest to call them infinite, until he reaches the fixt stars. No longer content with numbering and naming the host of heaven, and marshaling them in constellations, this tiny creature must take upon himself to scrutinize their constitution, must weigh their floating bulk, must "Speed his flight from star to star, From world to luminous world, as far As the universe rears his flaming wall," and, as if bearing in this amazing flight the measuring-rod which once the prophet saw in an angel's hand, must measure the paths along which the planets travel, and tell in human language the distances on the chart of heaven.