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KD5NJR > TECH 13.08.16 08:25l 95 Lines 3845 Bytes #999 (0) @ WW
BID : S12VZ3URND32
Read: GUEST
Subj: Re: Slide Rules
Path: IW8PGT<CX2SA<N0KFQ<AE5ME
Sent: 160813/0526Z 42758@AE5ME.#NEOK.OK.USA.NOAM BPQ1.4.65
I've enjoyed watching what's come and gone on this web site over the years.
http://www.sphere.bc.ca/test/sliderule.html
Have a great weekend.
73
Scott
kd5njr
----- Message from kf5jrv@kb0wsa.mo.usa.na sent 2016/08/07 14:02 -----
Message ID: 7275_KF5JRV
Date: 2016/08/07 14:02
From: kf5jrv@kb0wsa.mo.usa.na
To: tech@ww
Source: AE5ME
Subject: Slide Rules
R:160807/1402Z 42483@AE5ME.#NEOK.OK.USA.NOAM BPQ1.4.65
R:160807/1402Z 7275@KF5JRV.#NWAR.AR.USA.NA BPQ1.4.65
Slide rules
The predominant calculating aid for nearly three centuries, the slide rule
came together gradually as mathematicians used Napier's logarithms in their
instruments. Slide rules came in many shapes and sizes, with different rulings
suited to their specific application.
The slide rule's origins can be traced to the British mathematician Edmund
Gunter(1581-1626). Gunter distinguished himself through the design of
calculating devices, and was the first to use logarithmic scales for physical
instruments.
He arranged logarithms into a scale, known as Gunter's line, which was then
made into a two-foot rule with one side marked with logarithms and the other
rulings for navigation (Image 1) . By using a logarithmic scale to enable the
conversion of multiplication and division into addition and subtraction, these
rules were the predecessor of the slide rule. The example shown here was made
by Robert Yeff in 1712, and was probably used as a general-purpose calculator
at sea, where it would have been referred to simply as a "Gunter."
"The true way of Art"
The slide rule proper is believed to have been invented in the 1620s, when the
Reverend William Oughtred (1574-1660) in Surrey put together two Gunter scales
and slid them alongside one another. This way, he could calculate without the
use of dividers, which were required to operate both the Gunter's scale and
the sector.
Oughtred then designed a similar apparatus using scales on concentric circles
in order to make the device more compact.
Whereas Napier had enthusiastically applied his talents to devise a number
of aids for calculation, Oughtred apparently despised instrumentation for its
own sake, and kept his methods private. He published a Latin treatise in 1631
only to mitigate a priority dispute with a former student over the device.
He eventually permitted another student to translate the work into the English
vernacular, but not without a cautionary message:
"That the true way of Art is not by Instruments, but by Demonstration: and
that it is a preposterous course of Artists, to make their Schollers only
doers of tricks, as it were Juglers"
Changing shapes and sizes
The linear slide rule most recognised today gained popularity in the latter
part of the 17th century. It used a sliding piece of wood in a larger 'stock'
with rulings on both pieces, with a cursor to align numbers.
For the first century of their existence, slide rules were typically crude and
inaccurate, owing to the poor scale-dividing technology available. But as time
went on, they became advanced and powerful tools for calculation.
The cylindrical slide rule shown here was developed in the late 19th
century by E. Thacher, and had a scale that was 40 times greater than a
standard linear rule, in addition to a magnifying glass for improved accuracy.
Thacher's model was just one of numerous new slide rule designs developed
during the instrument's lifetime. Many were developed for use in specific
tasks, such as calculations relating to brewing or the measurement of
radiation doses. Other designs purported to be 'universal' instruments,
capable of solving numerous different types of numerical problem.
73, Scott kf5jrv
KF5JRV @ KF5JRV.#NWAR.AR.USA.NA
[End of Message #7229 from KF5JRV]
73, Scott kf5jrv
KF5JRV @ KF5JRV.#NWAR.AR.USA.NA
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