326 QUARTZ FIBERS. 



Being then in this difficulty I was by good fortune and necessity led 

 to devise a process which 1 propose at once to show you. I shall not 

 describe the preliminary experiments, but simply describe the process 

 as it stands. There is a small cross-bow held in a vice, and a little 

 arrow made of straw with a needle point, and I have here a fragment 

 of rock crystal which has been melted and drawn into a rod. It re- 

 quires a temperature greater than that developed in any furnace to 

 melt this material so that it may be drawn out. If the arrow, which 

 also carries a piece of the quartz rod, is placed in the bow, and if both 

 pieces are heated up to the melting point and joined together, and then 

 the arrow is shot, a fiber of quartz is drawn, — that is to say, it is drawn 

 if there is not an accident. 



The arrow has flown, and there is now a fiber not very fine this time, 

 which I shall hand to our president. At the same time I can pass him 

 a piece of much finer fiber, made this afternoon, which shows (and this 

 is a proof of its fineness) all the brilliant colors of the spider line when 

 the sun shines upon it, but with a degree of magnificence and splendor 

 which has never been seen on any natural object. 



The main features of these fibers are these. You can make them as 

 fine as you please; you can make them of very considerable length; 

 you can make pieces 40 or 50 feet long, without the slightest trouble, at 

 almost every shot. Even though of that great length, they are very 

 uniform in diameter from end to end, or at any rate the variation is 

 small and perfectly regular. The strength of the fiber is, I think I may 

 safely say, something astonishing. Fibers such as I have in use at the 

 present time in an instrument behind me are stronger than ordinary 

 bar steel ; they carry from CO to 80 tons to the square inch. That is 

 one of their most important features, for this reason, — that on account 

 of their enormous strength j^ou can make use of very much finer fibers 

 than would be possible if they were not so strong; and I have already 

 explained the importance of the fineness of the fiber when delicacy is 

 of the first importance. 



As to the diameter of these fibers, I have said they can be made as fine 

 as you please. I shall not trouble you with a large number of figures, 

 but one or two may probably be interesting to those who are in the 

 habit of using philosophical apparatus. In the first place, a fiber a 

 great deal finer that a single fiber of silk (that is, one five-thousandth 

 of an inch in diameter), will carry an apparatus more than 30 grains 

 in weight. I have in one of the pieces of apparatus which I shall use 

 presently, a fiber the fifteen-thousandth of an inch in diameter. That 

 is, so fine that if you were to take a hundred of them and twist them 

 into a bundle you would produce a compound cable of the thickness of 

 a single silkworm's thread. I do not mean the silk used for sewing that 

 is wound on a reel, because that is composed of an enormous number 

 of silk threads : but a single silkworm's thread as it is wound from the 



