sand uplifted faces as perfectly as the human eye perceives the feat- ures 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 nie 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. School- boys 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 Exist- ence. Ten minutes later, and it may be not a single person here rep- resented will be walking or riding along this street, yet the scene it- self 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 hiero- glyph 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 sight- seers, 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 arrest- ing eye might have seen Louis XVI, bending his head to the axe ; and another day caught Marie Antoinette's look, as she glanced back- ward 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-