LFSSOJVS IN ELECTRICITY. 



609 



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 gi-aceful nor pleasant. By 

 practice alone, you learn to dance and to play. This also is the only 

 way of learning the art of expei'iment. You must not, therefore, be 

 daunted by your clumsiness at first ; you must overcome it, arud ac- 

 quire skill in the art hy repetition. 



By so doing you will come into direct contact with natural truth 

 you Avill think and reason not on what has been said to you in books, 

 but on<H\'hat has been said to you by Nature. Thought springing from 

 this source has a vitality not derivable from mere book-knowledge. 



Sec. 4. Materials for Experiment. At this stage of our labors 

 we are to provide ourselves with the following materials: 



a. Some sticks of sealing-wax. 



h. 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, ca- 

 pable of being folded into pads of two or three 

 layers, about eight or ten inches squai'c. 



e. A couple of pads, composed of three or 

 four layers of silk, about eight or ten inches 

 square. 



/. 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. 



VOL. Till. 39 



Fig. 1. 



