El Paso herald. (El Paso, Tex.) 1901-1931, 1910-02-05

kinds of matter in the star from whence
I the beam comes. In this way the spec
: troscope found helium in the sun. So
/ 600 600 miles distant, before the chemist
! discovered it hard by his OVID door
! step.
7 The spectroscope has hundreds Of
uses, some of them very prosaic In the
: Bessemer process of making steel the
object is to burn certain percentage
/ OF the carbon out of the ore. 1t usual
/ ly takes about 20 minutes to complete
/ the process. but If it is poured out 20
! seconds too soon or 20 seconds too ate,
! the whole is ruined. The spectr0scope
! tells the exact instant when the proper
amount OF carbon has been burned out
Yerkes Telescope.
A remarkable instance of precision
in big things is the case of the great
Yerkes telescope. A star Of the seventh
magnitude appears to be One-twenty-
| five-hundredth of an inch in diameter
| There is a spider web across the object
! glass which is One-Six-thousandth of an
inch in diameter. The problem is to
move this % ton telescope with such
| precision that the star disc of one
| twenty five-hundredth of an inch can
be threaded upon the spider web Of
! ne-six-thousandth of an inch at all
, times, and to keep ii moving in opposi-
ton to the motion OF the earth This
lis accomplished by electrical attach
ments of wonderful accuracy
The strength testing machines now
! in use represent a high type Of exact
mechanism, possessing, as they do. the
| strength Of a thousand giants, and at
| the same time the delicacy Of the hair
spring OF q watch.
/ They register at one effort the ten
sile strength of bar of iron requiring
1000, 900 pounds to pull it apart. and
at the next effort tell to the fraction
of an ounce how much pressure is re-
quired to crush an egg she'll They win
test the strength Of a horse hair or
that of a gigantic cable with equal
exactness.
This machine operates on the prin-
ciple of the hydraulic press-2O0 grains
| of weight on one platform lifting TO-
GOO pounds on the other.
The MicrotOme.
The microtome is another remarkable
instrument of the laboratory. The per-
son who has seen the breakfast bacon
! slicer in grocery store will understand
something Of its principles.
When the scientist wants to exam
inc the cross section of a little cor
I puscle too small to be picked up with
the hand. he encloses ii in a coating OF
hard paraffine an5 that in another
| coating of softer consistency. Then he
puts In into his little slicing machine
and is able 10 make slices so thin that
it would require $4,000 Of them piled on
top of one another TO make a stack an
inch high. Then he melts the paraffine
away and places the almost invisible
slice on the object glass of his micro
scope.
! Time Measuring Machines.
Time measuring instruments of pre-
/ f-T.0
delicate machines OF science. Ever
since man has navigated the seas be-
yond the sight of land, he has needed
! the most accurate measures OF time. in
/ order that he might tell his longitude
/ with reasonable correctness. In 1714
| the English government offered 10000
/ pounds sterling TO the man who would
! devise a chrOnOmeter so accurate that
longitude could be told within 80
miles, and a descending reward down
! to half as much for the person who
/ could tell 1t within so miles.
|. In 1865 John Harrison, son OF York
| shire carpenter. claimed and was given
/ the highest award. Now chronometers
are made which are so accurate that
| they will vary only a few seconds in
weeks The usual battleship carries
three chronometers, and the mean time
| of the three is taken as actual time.
| Tiny Screws for Watches.
There are machines in common use
| today which make screws so small that
! they appear to be but little particles of
/ dust, 100000 of them being required 10
/ fill an ordinary thimble, Yet each Of
them must have a perfect head and
perfect thread They are used as screws
/ for the fourth jewel wheel of a watch.
All the operations with them are done
more by the sense of touch than Of
! sight, and IL IS marvellous how acute
/ the human sense Of touch may become
Sometime ago a bicycle manufactur-
er brought some balls intended for ball
1 bearings to a matchmaker to show
what perfect specimens he had pro-
duced. The matchmaker said they were
not round and wagered that he could
point out three depressions on each
/ ball A micrometer was applied and 1t
, showed that on each ball at the exact
spots pointed out, there were depres-
sions of less than the thousandth part
/ of an inch.