CHAPTER II.
SIMPLE AND COMPOUND MICROSCOPES--EVOLUTION OF THE MODERN ACHROMATIC MICROSCOPE--IMPROVEMENTS IN THE MODERN MICROSCOPE: THE ROSS-JACKSON, POWELL AND LEALAND, BECK’S, BAKER’S, PILLISCHER, ZEISS, LEITZ, WATSON’S, VAN HEURCK’S EDINBURGH STUDENTS’, SWIFT’S, AND BACTERIOLOGICAL 72