318 



QUARTZ FiBERS, 



physicist's disposal have until lately been simply limited by the behavior 

 of silk. A more perfect suspension means still more perfect instruments, 

 and therefore advance in knowledge. 



It was in this way that some improvements that I was making in an 

 instrument for measuring radiant heat came to a dead-lock about 2 years 

 ago. I would not use silk, and I could not tiud anything else that would 

 do. Spun glass even, was far too coarse for my purpose ; it was a 

 thousand times too stift". 



There is a material invented by Wollaston long ago, which however 

 I did not try because it is so easily broken. It is platinum wire which 

 has been drawn in silver, and finally separated by the action of nitric 

 acid. A specimen about the size of a single line of silk is now oh the 

 screen, showing the silver coating at one end (Fig. 5). 



As nothing that I knew of could be obtained that would be of use to 

 me, I was driven to the necessity of trying by experiment to find some 

 new material. The result of these experiments was 

 the development of a process of almost ridiculous 

 simplicity which it may be of interest for me to show. 

 The apparatus consists of a small cross-bow, and 

 an arrow made of straw with a needle point. To 

 the tail of the arrow is attached a fine rod of quartz 

 which has been melted and drawn out in the oxy- 

 hydrogen jet. I have a piece of the same material 

 in my hand, and now after melting their ends and 

 joining them together, an operation which produces 

 a beautiful and dazzling light, all I have to do is to 

 liberate the string of the bow by pulling the trigger 

 with one foot, and then if all is well a fiber will have 

 been drawn by the arrow, the existence of which can 

 be made evident by fastening to it a piece of stamp 

 paper. 



In this way threads can be produced of great 

 length, of almost any degree of fineness, of extraor- 

 dinary uniformity, and of enormous strength. I do 

 not believe, if any experimentalist had been prom- 

 ised by a good fairy that he might have anything he 

 ii\ desired, that he would have ventured to ask for any 



one thing with so many valuable properties as these 

 fibers possess. I hope in the course of this evening 

 to show that I am not exaggerating their merits. 



In the first place, let me say something about the 



degree of fineness to which they can be drawn. 



There is now projected upon the screen a quartz 



fiber one five-thousandth of an inch in diameter (Fig. 



0). This is one which I had in constant use in an instrument loaded 



with about 30 grains. J t has a section only one-sixth of that of a single 



