sand uplifted faces as perfectly as the human eye perceives the features of a single countenance. Every expression of joy or sorrow, every peculiarity of dress or attitude, the leaves of a forest or the grass by the wayside, will have been seen and delineated and retained perfectly in far less than the briefest possible twinkling of a human eye.
Before me as I write is an instantaneous photograph upon glass of one of the principal boulevards of Paris, taken about noon-time. I seem to be looking down a broad avenue of lofty houses, each six stories high. I can see seven street crossings or blocks. The avenue is lined with shade-trees on either side. The street is filled with a moving panorama. So exquisitely fine are all the details that, to bring them out, I must use a small hand-microscope. Nearly fifty vehicles of every kind are in sight, all in position of arrested motion. A block distant an omnibus is approaching; the very foot-board slats upon which a passenger rests his feet I can count with my microscope. The sidewalks are crowded with every variety of Parisian costumes. Near me is a soldier touching his hat to his superior officer as he passes him, and three blocks away I can see a man sweeping the street. Schoolboys and clerks, shop-girls and mechanics, soldiers and street-sweepers, gentlemen of leisure and rambling travelers, representing every type of Parisian life, are all here. It is a picture of a Moment of Existence. Ten minutes later, and it may be not a single person here represented will be walking or riding along this street, yet the scene itself will be unchanged. The crowd continues; the atoms change.
Here is another Paris view, of a spot infinitely interesting to the historian, the Place de la Concorde. Almost in exact range we see the two fountains on either side of the Obelisk of Luxor; a quarter of a mile beyond is the Church of the Madeleine. The same ever moving crowd of human activities is here again unconsciously arrested on this plate of glass! There rises the Egyptian Obelisk, every hieroglyph as clear as when first raised in Egypt two thousand years ago. Ah! if human invention could have caused this eye to preserve for us but one glance of the awful tragedies which have been enacted on this spot! In place of those romping school-boys or laughing sightseers, once gathered on this place an eager, hungry, and bloodthirsty crowd of men and women; where that obelisk points to heaven once stood a platform, and thereon the guillotine. And one day this arresting eye might have seen Louis XVI, bending his head to the axe; and another day caught Marie Antoinette's look, as she glanced backward toward the Tuileries; or Madame Roland apostrophizing the Statue of Liberty; or Charlotte Corday murmuring, "The crime, and not the scaffold, makes the shame!" And imagine the upturned faces of that crowd!
But not only is the range of vision vastly more comprehensive by the photographic camera; it is far keener. The sensitive plate of the photographer is to-day of special use in the observatory of the astrono-