THE YOUNG SCIENTIST. 
11 
Notes on My Cabinet— Silk and Flax. 
IN a former article I showed my young- 
readers the difference between cotton 
and wool ; I now give figures of flax and 
;silk, which show very clearly the charac- 
teristics of these fibres. It will he seen 
that while silk is a smooth, even fibre, 
like a wire, or like spun glass, flax is ir- 
regular and knotted like a bamboo cane. 
In examining dry goods, for the purpose 
of finding out what they are made of, it is 
SILK. FLAX. 
well to bear in mind the following facts in 
regard to the origin of these different 
fibres. Wool is an animal hair, covered 
with scales, which give it its imbricated 
appearance. It is round, solid and even, 
and under the microscope the prominent 
feature is the scales. Cotton is a vegetable 
hair which, when growing, formed a tube 
filled with liquid. When the hair dried 
the sides of the tube came together so as 
to form a flat ribbon. 
Flax is the tissue of the stem of the 
plant. Instead of being smooth, like 
•cotton, it is hard and solid, and as each 
fibre has been torn apart from its fellows, 
it is rough when contrasted with cotton 
or silk. Many attempts have been made 
to break the flax up into fibres so fine that 
they could take the place of cotton. Often 
and often we have been shown "flax-cot- 
ton," as it was called, which the inventors 
thought could not be distinguished from 
real cotton. Under the microscope the 
difference was at once visible, and when 
worked in the ordinary cotton machinery 
it showed its character very plainly. 
Silk is a fine fibre spun by the silk worm 
as a covering (cocoon) to protect itself 
while in a dormant state. The silk fibre 
is really a solidified liquid. The w^orm 
draws the viscid, tough liquid out of its 
spinnerets, and the fine thread thus pro- 
duced hardens when it comes in contact 
with the air. Silk, therefore, has no struc- 
ture, as it is called — that is to say, it is not 
composed of cells like flax or wool, but is 
the same throughout just like wire or spun 
glass. The gut used by fishermen is the 
san]e thing, but thicker fibres. Instead of 
being spun by the worm, however, it is 
sinm by men who kill the worm, expose 
the bag of liquid, and draw it out so as to 
form a thread of the desired length and 
thickness. Gut is, therefore, merely a 
stout thread artificially produced from 
the same substance that is used by the 
silk worm to produce silk. o, w. 
A Cheap and Simple Camera for the 
Microscope. 
THE following capital little device is de- 
scribed by Mr. T. B. Jennings, in the 
American Journal of AiUTOScopy, and we 
republish it from advance sheets of that 
journal : 
Probably there is nothing that will 
assist the student in microscopy so thor- 
oughly as drawing the object, as he 
thereby fixes the different parts in his 
mind. 
A good camera lucida is too expensive 
for many persons, while other and more 
necessary accessories are being purchased. 
Having made a good reflector for my 
own use at no expense, and thinking that 
many of your subscribers might desire to 
do the same, I give the mode. 
Take a flat cork. Fig 1, a (mine was 
from a large-mouthed bottle), cut a hole, 
b, through its centre large enough to fit 
over the eye-piece after the cap has been 
