649. Value Of Photographs

Value Of Photographs. This photographic illustration clearly shows the actual value of photography in illustrating the progress made during the growth of the seed to a fully developed plant.

G50. Development of the Twig. - Another interesting subject, and one which is usually given consideration in public schools, is the making of records to show the development of twigs. In the early spring, just as the buds begin to burst, a collection of different twigs should be procured and these placed in test tubes of water. The larger the variety of these subjects the greater will be the value of such a record, for the series of photographs will show the rapidity of the development of one subject over another. In Illustration No. 118, the twigs used were (reading from left to right), maple, plum, apple, sumach, chestnut, poplar, blackberry and walnut. The photographs were made every two days for these four illustrations. Fig. 5, Illustration No. 119, shows the subjects in their respective test tubes in the rack. Fig. 6 of this same illustration shows these twigs at the end of three weeks growth. The intermediate stages between Fig. 4 and Fig. 6 have been omitted, but the student should make negatives at regular intervals (every two days) up until this time, in order that the record may be complete in every respect.

651. Other Subject Material

Other Subject Material. These two series of subjects are given to illustrate the application of photography to botanical work, but photography can be applied wherever a drawing is required. For instance, a valuable record may be obtained of the construction of different leaves, the veins, etc., all being accurately reproduced.

652. Photographing Leaves

Photographing Leaves. The most satisfactory method of photographing leaves to show the veining is to place the stem of the leaf in red ink and allow it remain there until the veins are completely filled, which will usually take about 24 hours; then lay the leaf carefully between two sheets of clear, clean glass and bind them together with lantern-slide binding or passe-partout tape. This subject may then be placed in the regular copying frame, as described in Vol. V, and an exposure made in accordance to the instructions given for copying. The result of proceeding in this manner will be a negative in which the veins of the leaves will be transparent, while in the final print they will be practically black, the fleshy part of the leaf being of a sufficiently lighter shade to contrast strongly with the veins. By placing the leaf between two sheets of glass the serrated edges and general outlines of the leaf will be accurately reproduced.

653. As previously stated, each and every experiment, not only in botany but in chemistry and other similar sciences, should be photographed, the views chosen being such as will show forth, to the best advantage, the important points which the student considers in his regular lesson work.