The Arizona sentinel., 1888-11-03
THE COMPTOMETER.
A Chicago Genius Invents a Marvellous
Calculating Instrument.

No one is ever surprised at any Curl
osity which turns up in Chicago, but
the one that has been lately unearthed
is well worthy of notice. They call it
a comptometer, or, in other words, q
calculating machine. The inventor,
Mr.. Smelt, is modest young man
who looks as if he might be school
teacher or divinity student, but, al
though he is only twenty-six years of
age, he has already, in various ways,
shown himself to be a man of rare
| inventive genius. of which the comp
tometer, or calculator, is the latest and
most important product.
The standard instrument is 14l
inches long, Il inches wide, 5 inches
high, weighs s pounds and can be
manipulated without Inconvenience on
any ordinary desk or table. 1t differs
from all former mechanical calculators
in that, like the typewriter, it is
worked altogether by keys.
Two or three instruments, with a
similar object in view, had been pre-
viously constructcd-notably one by a
Kentucky monk-which were capable
of making computations in the rule of
addition, but with only one column of
keys, leaving part of the work to be
performed mentally. whereas Mr..
Felt'S invention carries all the columns
in sums of addition at the same time,
and performs all operations, even to
the smallest fraction-as well as to the
highest power in billions in the four
fundamental rules of arithmetic, on
eight columns of keys.
An expert on this instrument can
work as rapidly as typewriter, and
the merest novice can work as rapidly
as the most expert accountant working
on the old mental system. Mr.. Joseph
Mccoy, acting Government actuary of
the United States Treasury Depart
ment, Washington, who has tried the
instrument, states that an intelligent
novice rapidly becomes the superior OF
the most skilled expert in the old
method. and he bases his assertion
upon the unfailing accuracy and speed
of the comptOmeter.
A gentleman present, when the in
strument was tested the other day. took
out his notebook and wrote down the
figures 4,7S2, which he proceeded to
multiply by SO as rapidly as he could.
Mr.. Felt brought his instrument into
requisition, and when the gentleman
had commenced to multiply with the
second figure the instrument had
recorded the full answer, 46S, ,636. The
number 4,7S2 was then multiplied by
ed the third figure of the multiplier
Mr.. Felt sang out the answer, 22,S67,-
524. The number 423 was then multi
piled by 476, and the result divided by
423, when the correct quotient was
reached by the instrument before the
nimble gentleman had commenced his
division. The following sum was then
tackled: Suppose you bring f234 from
England to New York, where the rate
of exchange is 4.S4B, what is the Amer
lean value of your money! In a second
the very-ready reckoner had reached
81, 134. COZ, while the slow but earnest
man was wrestling with the preliminary
fraction.
In reference to the speed and accu-
racy of his instrument Mr. Felt said:
''When l was in Washington last year
l was invited by officials of the Treas
ury Department to exhibit the compto-
meter in the presence of experts. Cen
eral Rosecrans was particularly inter-
ested in the instrument, but was unable
to be present at the expert test. Those
experts are certainly 'dandies' at their
craft. They are mighty smart fellows,
and l felt considerable timidity about
a tussle with them. However, the Of
fetal who acted as examiner gave out
five long sums in the four rules. The
experts worked away with their pencils
and l with my instrument.
''In four cases out of the five l fin
ished frst-though am only a novice
and my answers were quite correct,
while all the experts, in their desper-
ate efforts to keep up with me, got off
the track and were wrong in every cal
culation. In the fifth case the experts
finished first, but were wrong, while
my answer was correct"
The mechanical construction of the
comptometer, under the supervision Of
the inventor, is as nearly perfect as
human skill can make it, all the oper-
ating parts being made of the finest
hardened steel, thereby insuring the
greatest degree of permanence and the
least degree of friction. AS an instance
of the expense incurred in perfecting
the instrument, 1t may be stated that
more dies are used in the construction
of comptometer than are to be found
in any typewriter. Chicago Letter.
A SinoItIay Exnarienca