Common Objects of the Microscope

Оглавление

John George Wood. Common Objects of the Microscope

PREFACE TO THE SECOND EDITION

PREFACE TO THE FIRST EDITION

CHAPTER I

CHAPTER II

CHAPTER III

CHAPTER IV

CHAPTER V

CHAPTER VI

CHAPTER VII

CHAPTER VIII

CHAPTER IX

CHAPTER X

CHAPTER XI

CHAPTER XII

Отрывок из книги

In my two previous handbooks, the “Common Objects” of the Sea-shore and Country, I could but slightly glance at the minute beings which swarm in every locality, or at the wonderful structures which are discovered by the Microscope within or upon the creatures therein described. Since that time a general demand has arisen for an elementary handbook upon the Microscope and its practical appliance to the study of nature, and in order to supply that want this little volume has been produced.

I must warn the reader that he is not to expect a work that will figure and describe every object which may be found on the sea-shore or in the fields, but merely one by which he will be enabled to guide himself in microscopical research, and avoid the loss of time and patience which is almost invariably the lot of the novice in these interesting studies. Upwards of four hundred objects have been figured, including many representatives of the animal, vegetable, and, mineral kingdoms, and among them the reader will find types sufficient for his early guidance.

.....

A still better stand, and one which is good enough for almost any class of work, is that shown in Fig. 8, which is known as the “Portable” microscope. In this instrument the body is made up of two tubes, so that the length may be varied at will, and this gives a very considerable range of magnification without changing the object-glass, a great convenience in practice; whilst the legs fold up for convenience of carriage, so that the whole instrument, with all necessary appliances, may be readily packed in a corner of a portmanteau for transport to the country or seaside.

The objectives supplied with the simplest form of microscope above referred to are combinations of three powers in one, and the power is varied by using one, two, or three of these in combination. This form of objective is very good, as far as it goes, though it is impossible to correct such a combination with the accuracy which is possible in manufacturing one of a fixed focal length.

.....