
Bissaker's Sturdy Slide Rule 
In 1654, Robert Bissaker designed and constructed the first slide rule whose slide was placed between two parts of a
fixed stock. This proved to be more durable than other slide rules previously designed, and in fact durable enough to
last to the twentieth century when slide rules weren't needed anymore. The one pictured above was actually made by Bissaker
and is the oldest known slide rule. Little is known of Bissaker other than he worked in London as a woodworker, primarily
making navigation tools for seamen. Bissaker also created a set of Napier's bones made out of wood, rather than
ivory.





Calculators


Slide Rule (1623)





The Slide Rule:
A Combined Effort

Slide Rule 
Napier had come up with a way to do munltiplication and division using logarithms, but still that took some work.
The search continued to find an easier and quicker way to multiply numbers. Edmund Gunter used Napier's logarithms
to create the precursor to the first slide rule. He created a number line with the numbers spaced out proportionate to
their logarithms. Then a product could be found by finding one of the factors on the number line, then letting that
become the new start and from that point count out the next value of the second factor. This sum is the product
of the two numbers. A few years later, William Oughtred came along and refined Gunter's idea by making two number
lines that could slide along each other, reducing the work of readjusting the starting point. In this case, the second
line was placed at the value of the first factor. The point of the second factor was marked on the line of
the first, marking the sum of the two numbers. This was then the product of the two numbers. Oughtred is credited
for invention of the first slide rule. Revisions were continuely made but used the original ideas of Gunter and Oughtred. A double cursor
was added in 1850 by French Artillery Officer Amedee Amnnheim. At this
time, the slide rule was called an astrolabe, due to it's significance in astrology. The slide rule held as
a common tool for many mathematicians and students of math for about three hundred years, until the emergence of the calculator
as we know it now.


Bio: Gunter
Edmund Gunter (15811626)
was schooled in London and Oxford where
he graduated in 1603. In 1615 he earned his degree in divinity and was
ordained. He held a position in the church until he died in 1626, but his main
interests remained in mathematics. In
1619, Gunter became the professor of astronomy at Gresham College in London. The year of 1620 was
a busy year for Gunter. Here is a list of some of his accomplishments in this
year: published seven figure tables of logarithms of sine and tangent; coined
the names cosine and cotangent, and the abbreviations sin and cos; and invented Gunter’s Scale, the twofoot long scale
that was the forerunner to the slide rule.

Edmund Gunter's publication 



Bio: Oughtred
William Oughtred (15741660) was also an ordained minister as well as a mathematician.
He went to school at King’s College Cambridge, receiving his B.A. in 1596 and his M.A. four years later. Oughtred was ordained an Episcopal minister in 1603 and though he served in the church,
his mathematics continued. He was a private tutor for many and was known for
his passion towards the subject of math. His accomplishments include: creating
an early form of the slide rule in 1623; inventing the circular slide rule in 1630; being the first to use x as a symbol for
multiplication and :: as a symbol for proportion (1631).





