Page:Popular Science Monthly Volume 8.djvu/627

 Rh It is an art of extreme importance, for by its means we can, as it were, converse with Nature, asking her questions and receiving from her replies.

It was the neglect of experiment, and of the reasoning based upon it, which kept the knowledge of the ancient world confined to the attraction of amber for more than 2,000 years.

Skill in the art of experimenting does not come of itself, it is only to be acquired by labor. When you first take a billiard-cue in your hand, your strokes are awkward and ill-directed. When you learn to dance, your first movements are neither graceful nor pleasant. By practice alone, you learn to dance and to play. This also is the only way of learning the art of experiment. You must not, therefore, be daunted by your clumsiness at first; you must overcome it, and acquire skill in the art by repetition.

By so doing you will come into direct contact with natural truth—you will think and reason not on what has been said to you in books, but on that has been said to you by Nature. Thought springing from this source has a vitality not derivable from mere book-knowledge.

Materials for Experiment.—At this stage of our labors we are to provide ourselves with the following materials:

a. Some sticks of sealing-wax.

b. Two pieces of gutta-percha tubing, about eighteen inches long and three-quarters of an inch outside diameter.

c. Two or three glass tubes, about eighteen inches long and three-quarters of an inch wide, closed at one end, and not too thin, lest they should break in your hand and cut it.

d. Two or three pieces of clean flannel, capable of being folded into pads of two or three layers, about eight or ten inches square.

e. A couple of pads, composed of three or four layers of silk, about eight or ten inches square.

f. A board about eighteen inches square, and a piece of India-rubber.

g. Some very narrow silk ribbon, and a wire loop, like that shown in Fig. 1, in which sticks of sealing-wax, tubes of gutta-percha, rods of glass, or a walking-stick, may be suspended. I choose a narrow ribbon because it is convenient to have a suspending cord that will neither twist nor untwist of itself.

I usually employ a loop with the two ends, which are here shown free, soldered together. The loop would thus be unbroken. But you may not be skilled in the art of soldering, and I therefore choose the free loop, which is very easily constructed.