To obtain a considerably magnified picture we must have a lens of short focal length and a camera with long bellows, in fact in theory the amount of magnification is only limited by the length of the bellows, so that an extraordinarily long camera should give us a much magnified picture. We cannot lengthen our bellows without considerable expense, but we can shorten the focal length of our lens. If we obtain, at the cost of a few pence, a convex lens of short focal length, such as is used in cheap magnifiers we can easily apply it to our camera lens and it will have the effect of shortening its focus. This extra lens can either be fitted in front of our original lens by cutting two inches of cardboard, of such a size that they will just fit into the lens hood. In the centre of each piece of cardboard, cut two circles, slightly smaller in diameter than the diameter of the convex lens. Place the lens over the opening in one of the pieces of cardboard and stick the other piece upon it with glue or seccotine. When dry fix the lens in its cardboard holder in the front of the lens hood and repeat the focussing experiment with the foot rule. We shall now obtain a much greater magnification with the same length of bellows, because the additional lens has shortened the focus of our original lens. Probably our camera is fitted with a double lens and it is possible to unscrew the front portion, in this event our extra lens with its cardboard holder may be fitted inside the front lens up against the diaphragm and the front lens replaced. The result is practically the same whatever the position of the new lens, but we must be certain that it is convex, for a concave lens would increase the focal length of the whole and so reduce our magnification. We may find that the amount of enlargement we can now obtain is sufficient for our purpose; if so we can go ahead and produce photo-micrographs of all the objects we desire. The methods of doing so differ in no way from those employed in taking ordinary photographs and as we are writing about microscopy and not photography in these pages, there is no need to go into further details. Even the experienced photographer, however, is liable to overlook one or two important details. The bugbear in all work of this kind, with low magnifications as well as high, is vibration. Not only is our object magnified but every movement is equally increased. No one should walk across the room while this work is in progress; in large towns, trams and heavy motors will ruin many a plate, in fact it is only when one takes up work of this kind that one realises that one’s house is in a perpetual quiver. Some enthusiasts work at the dead of night, others suspend their apparatus on springs and invent all kinds of ingenious devices to overcome these miniature earthquakes.