Half-hours with the microscope : being a popular guide to the use of the microscope as a means of amusement and instruction / illustrated from nature by Tuffen West.

  • Tuffen West
Date:
[1875?]
Catalogue details

Licence: Public Domain Mark

Credit: Half-hours with the microscope : being a popular guide to the use of the microscope as a means of amusement and instruction / illustrated from nature by Tuffen West. Source: Wellcome Collection.

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    and attached to the Simide :Microsco])e, they are called doublets and triplets. The magnilying-glasses which are niaile to be held in the hand, Ireqiieutly have two or three gla.sses, by which the power ot the instrument may be increa.sed or decreased, buch instruments as these were the first which were em- ployed by microscopic observers; ami it is a jiroot of the essential nature of this part ot the Micro- scope, that many of our greatest discoveries have been made with the Simple Microscope. The nearer the glass or lens is bi’ought to an object, so as to enable the eye to see, the more ot the object will be .seen. So that when we u.se a glass which enables us to see within one inch ot an object, we see much more than if we could bring it within only an inch and a half or two inches. So on, till we come to distances so small as the eighth, sixteenth, or even twentieth of an inch. Although a great deal may be seen by a common haud-glas.s, such as may be purclnuscd at an opti- cian’s for 7s. Gd. or half a guinea, yet the hand is unsteady, and if they were made with a very short focus, it would be almost iinjtossible to use them. Besides, it is very desinvble in examining objects, to have both hands free. On these accounts the glas-ses, which in such an arrangement are called object-ylasses, are attached to a sUmd ami placed in an arm which moves up and down with rack-work. In this way, the distance of the object from the glass can be regulated with great nicety. Under- neath the glass, and attached to the same stand, is a little plate or framework, to hohl objects, which are placed on a piece of glass. This is called t/ie stage. Sometimes rack-work is added to this stage, by which the objects can be moved upon it back- wards and forwards, without being moved by the hand. Such an arrangement as this is called a