way threads can be produced of great length, of almost any
degree of fineness, of extraordinary uniformity, and of enormous
strength. I do not believe, if any experimentalist had been promised
by a good fairy that he might have anything he 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.

[Illustration: FIG. 6.]

[Illustration: FIG. 7.]

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. 6). This
is one which I had in constant use in an instrument loaded with about
30 grains. It has a section only one-sixth of that of a single line of
silk, and it is just as strong. Not being organic, it is in no way
affected by changes of moisture and temperature, and so it is free
from the vagaries of silk which give so much trouble. The piece used
in the instrument was about 16 inches long. Had it been necessary to
employ spun glass, which hitherto was the finest torsion material,
then, instead of 16 inches, I should have required a piece 1,000 feet
long, and an instrument as high as the Eiffel tower to put it in.

There is no difficulty in obtaining pieces as fine as this yards long
if required, or in spinning it very much finer. There is upon the
screen a single line made by the small garden spider, and the size of
this is perfectly evident (Fig. 7). You now see a quartz fiber far
finer than this, or, rather, you see a diffraction phenomenon, for no
true image is formed at all; but even this is a conspicuous object in
comparison with the tapering ends, which it is absolutely impossible
to trace in a microscope. The next two photographs, taken by Mr.
Nelson, whose skill and resources are so famous, represent the extreme
end of a tail of quartz, and, though the scale is a great deal larger
than that used in the other photographs, the end will be visible only
to a few. Mr. Nelson has photographed here what it is absolutely
impossible to see. What the size of these ends may be, I have no means
of telling. Dr. Royston Piggott has estimated some of them at less
than one-millionth of an inch, but, whatever they are, they supply for
the first time objects of extreme smallness the form of which is
certainly known, and, therefore, I ca