Page:Popular Science Monthly Volume 91.djvu/140

This page needs to be proofread.


��Popular Science Monthly

��of water; in fact, the former may be preferred to it, for, although it necessitates a somewhat longer exposure, it is free from evaporation and is not so likely to be jarred out of place, on account of its superior capillary attraction.

���At left: Microtomic cross-section of a rue leaf. Right: The hair on the leg of a housefly

A standard must next be constructed, as shown at H, and /. No dimensions will be given as the construction will vary with the type of camera employed. Near the top of the standard a 34-in. stovebolt, J, should be inserted and screwed into the tripod socket, thus holding the camera in place.

The adjustable slide-holder is next to be considered. Some time was spent and a quantity of material utilized in devising methods of construction for this important part. The one which proved to be the most successful is shown at K. It represents a piece of H-in. wood (a cigar box will do) in which a ij^-in. hole, L, was cut. On each side of this hole a 5/32-in. bolt, M, was in- serted and made stationary by the nuts N. A long battery bolt will serve the purpose excellently. Another piece of K-in. stock, 0, somewhat longer than the other, with a i3^-in. hole as shown at T, was also made. To one end of this second piece there was nailed a 3^-in. square strip, P, which served to fasten the whole part to the standard. On either side of the ij^-in. hole of the second piece, there was bored a hole cor- responding to the bolts, M, and large enough to permit them to slide up and down easily. Springs, Q, were then slipped on the bolts, which were in turn passed through the corresponding holes in O. Thumb nuts, R, such as are found on batteries, were then screwed on the bolts. By tightening or loosening the thumb nuts, the slide-holder was adjusted to the lens. A strip of spring brass, S, was then fastened on K, to hold the slide rigid. When it was desirable to use a color-screen in photo- graphing or examining any object, the filler was laid over the hole, T, on J. The

��adjustable holder was then mounted by means of a strip, P, on the standard near the lens U, in the shutter, V. On account of the great magnification the focus is necessarily very short; indeed, it has been found that when a 6-in. bellows extension is used, the focus is not quite 1/16 in.

An adjustable mirror, W, must be mounted on the standard base, H, by means of an axle working on pivots in the strip X.

To operate, the object to be photo- graphed must be placed on a thin glass slide which should be fastened by means of the spring brass clip, S, over the hole, L, in strip, K. The bellows containing the water lens must be extended as far as possible. The mirror, W, should be adjusted until the direct sunlight is reflected through the slide into the camera. Focus- ing is then accomplished by tightening or loosening the thumb nuts, R, as the case may be. The plate is then placed in posi-

���An ordinary camera attached to support for making microscopic views with a water lens

tion and the actual photographing carried on as usual. An old magic lantern may be used as the source of illumination; but

�� �