As soon as you have a microscope you will begin to look at everything and anything: dust, crumbs of bread, flour, starch, mosquitoes, flies, and moth millers in their season; flowers and leaves, cotton, wool, and silk. But this scattering kind of observation will soon weary you. In order to get the greatest pleasure and best results from your work, you must proceed with some system.
BULL'S EYE LENS.
MAGNIFIED 50 DIAMETERS.
There are so many objects visible only through the microscope that life is not long enough for you to see them all, much less to study them. Some microscopists devote the time they have for such studies to the observation of single classes of objects; the physician observes the various parts of the animal structure, and calls his work "histology;" the botanist examines the vegetable kingdom; the entomologist, insects; but in all these departments there are numerous subdivisions. As a guide to your work, you will find some book on the microscope very useful; the best one is The Microscope and its Revelations, by Dr. William B. Carpenter.
FLY'S EYE—5 DIAMETERS.
Objects through which you can see light are called "transparent," and are the easiest to look at with the microscope, because you can lay them on a glass slide and throw light up through them with your mirror. Thick objects through which light cannot pass are called "opaque," and are more difficult to examine, and can only be seen with low powers and a bright light.
In order to see such objects in the evening, you will need a "bull's eye" lens mounted on a stand, which you can place beside your microscope and between the lamp and the stage, condensing the light of the lamp on the object. (Fig. 1.) There are other methods of illuminating opaque objects, but they are expensive and difficult to manage, yet by and by if you persevere in this delightful occupation you will learn what they are.