638. Introduction

Introduction. It is always essential to have records of plant growth, as well as of the arrangement of apparatus used for the various experimental sciences. In the past it has been customary for the student to make drawings of the various stages of plant growth, and to illustrate, by means of the pencil, the various experiments in chemistry and mechanics. The object of making these illustrations is not to train the student in the art of drawing so much as it is to secure a record which can be placed in the note-book, to show the experiment more clearly than is possible to describe it in words.

639. It is a generally conceded fact that the average student is a poor draftsman and fails, in many instances, to give a proper rendering of his subject; thus the drawing does not give an exact record.

640. Colleges and universities, as well as many of the public schools, are resorting to the use of photography, making a practical application of it. In no place will it be found more valuable than in making botanical records and showing the arrangement of experimental apparatus used in the various sciences, such as chemistry, electricity, etc.

641. Inexpensive Process

Inexpensive Process. One negative of an experiment is all that is required, as an unlimited number of copies may be secured from it, thus giving each student a perfect record of the experiment to place in his note-book. The expense is practically no greater than the procuring of drawing materials, and the loss of the time required to make a drawing, by each individual member of the class, is avoided.

642. Photographing Seeds

Photographing Seeds. Usually one of the first records made by students in botanical classes is that of the development of a plant from the seed. In the first of the series of illustrations accompanying this instruction - Illustration No. 115 - is shown the manner of procedure. In order to photograph seeds to the best advantage, they should be placed in a diagonal position to the camera (See Fig. 1). The usual method of starting a seed germ is to saturate a blotter with water and lay it on a board. On top of this place a layer of cotton, also saturated with water, and then lay the seeds in place. For experiment we have selected three lima beans, three black beans, three golden-eyed wax beans, three kernels of corn and six peas. Another strip of cotton is saturated with water and carefully laid over the seeds; the first photograph being made, however, previous to drawing the upper layer of cotton over the seeds.

643. Daily Records

Daily Records. The photographic records should be made daily and at approximately the same hour of the day. This is comparatively easy, as class periods are usually at the same time.

644. Location Of Camera

Location Of Camera. The distance between the lens and the subject in every record made of the same series should be the same. For ascertaining its distance, a yard or meter stick will be a convenient accessory. The object of always having the camera at the same distance from the subject is to show in a most accurate manner, the actual development which takes place from day to day.