CONTENTS.

CHAP. I.

A concise History of the Invention and Improvements which have been made upon the Instrument called a Microscope. [p. 1].

CHAP. II.

Of Vision; of the optical Effects of Microscopes, and of the Manner of estimating their magnifying Powers. [p. 26].

CHAP. III.

A Description of the most improved Microscopes, and the Method of using them. [p. 64].

CHAP. IV.

General Instructions for using the Microscope, and preparing the Objects. [p. 129].

CHAP. V.

The Importance of Natural History; of Insects in general, and of their constituent Parts. [p. 167].

CHAP. VI.

A general View of the internal Parts of Insects, and more particularly of the Caterpillar of the Phalæna Cossus. A Description of sundry miscellaneous Objects. [p. 334].

CHAP. VII.

The Natural History of the Hydra, or Fresh Water Polype. [p. 357].

CHAP. VIII.

Of the Animalcula Infusoria. [p. 415].

CHAP. IX.

On the Organization or Construction of Timber, as viewed by the Microscope. [p. 574].

CHAP. X.

Of the Crystallization of Salts, as seen by the Microscope; together with a concise List of Objects. [p. 600].

CHAP. XI.

An Arrangement and Description of minute and rare Shells. A descriptive List of a Variety of vegetable Seeds, as they appear when viewed by the Microscope. By the Editor. [p. 629].

CHAP. XII.

Instructions for collecting and preserving Insects. A copious List of microscopic Objects. By the Editor. [p. 665].

ADDITIONS. [p. 713].