The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1890-05-11
The LAWS OF CHANGE
Calculation BY Mathematical AethodS Of
the Probability Of Certain Events.
Deciding the Authorship OF Liter
airy Compositions BY Means of
an I~ngeniously Devised
Word Spectrum.

Some days ago Prof. T.. {. Mendenhall
OF the geographical survey lectured at the
National museum at Washington on
'Chance and the Long Rum" In the be-
ginning Of the lecture, says the Washing
ton Star. Professor M~endenhall referred
briefly 70 the history Of the doctrine of
chance or the law OF probability, saying
that 1t had its real origin in the work of
Pascal, who in about the year of 1884 was
called upon to settle a dispute between
W gamblers. From the time of Pascal
to h present the subject had received
the consideration of the ablest mathema-
ticians, including especially the great La
place, and nearly every great mathemati-
cal scholar had contributed TO its growth.
Then he proceeded to show that the
probability, or chance, or facility of an
event might be expressed fundamentally
by means of a fraction. When the value
Of this fraction was one the event was
certain to happen. References were
made, in illustration, to the tossing of
coins. throwing dice, drawing balls from
jars, DC. 1t is possible to calculate the
probability OF some very complex events,
and the processes involve the use of very
difficult mathematical methods. 1t was
therefore desirable to verify the result of
this mathematical treatment Of the sub
ject by means of experiment. Sew
eral experimental tests of the doc
trine OF chance were described. IL
was possible to calculate the probability
that a short stick i'm falling on a surface
ruled with parallel lines would or would
not lie across N of those lines. Having
computed this probability, Professor
M~endenhall said that he had verified the
result by pitching a stick upon such a sur
face and noting o il fell 1000 times.
This is probably the most experimental
test ever applied,
The numerous applications of the laws
of chance were next referred to. Espe-
cial attention was given TO its use in ex-
pressing the credibility Of human testi-
mony and determining its weight. II the
credibility OF a man were expressed by
the fraction four-flfths il meant that what
he said would i'm the long run be true four
times out of five. Reasons were given
for believing that the average credi bility
was about three-fourths, in which was in
Guided not only any tendency to lie which
might exist, but also the chances of being
mistaken. Ii was stated that il the credi-
bility OF witnesses were one-half. one
witness was as good as 100; IL il were less
called the better, and if more than one
half additional testimony would
strengthen the evidence.
Some of the ~fallacies of gamblers were
referred to, and illustrations were given
TO show their absurdity. II was shown
Nhfhs kttti'o Vi taitN ttsiutH' al "
gain were bad from a ''business stand
point" IL from no other, and i'm any case
the loss was greater IA the gain"
An application of the laws of 'chance
and the long run" was made in a pro-
posed plan for detecting authorship by a
sort OF word analysis. The method de-
ponds on two or three assumptions.
The nature OF the process, The speaker
said. is extremely simple, but il may he
useful TO point out its similarity TO n we'll
.a..,. a - IL
consideration of which actually first sug-
gested to the writers its literary analogue.
BY the Use of the spectroscope a beam of
neutrality-suspicious. light is analysed. and
its ~components assorted according TO
their wave length. As is well known,
each element, when intensely heated un-
der proper conditions, sends forth light
which, upon prismatic analysis, is found
to consist of groups OF waves of definite
length and appearing in certain definite
proportions. So certain and uniform are
the results of this analysis that the APP
pearance OF a particular spectrum is in-
disputable evidence of the presence of the
element TO which il belongs.
In n manner very similar IL is proposed
to analyze a composition by forming what
may be called a sword spectrum or
characteristic curve" which shall be a
graphic representation of am range
ment of words according to their length
and to the relative frequency of
their occurrence. If now il shall be found
that with every author, as with every ele-
ment, this spectrum persists in its own
form and appearance, the value of the
method will be at once conceded. Ii has
been proved that the spectrum of hydro
gen is the same whether that element is
obtained from the water of the ocean or
from the vapor of the atmosphere.
Wherever and whenever il appears il
means hydrogen. If il can be proved
that the word-spectrum or characteristic