slide rule

The slide rule is a mechanical analog computer.

The rulers each have a logarithmic scale(the spacing between the lines on the scale become smaller as the value increases), it is possible to align them to calculate the product of two numbers.

The Slide Rule

Cursor is a glass indicator.
Black scales increase from left to right.

C & D scales are single (1-10) scales.
A & B scales are double (1-10-100) having two cycles
K is triple (1-10-100-1000) having three cycles

Red scales increase from right to left.

CI & DI scales are single (1-10) scales.

Trig scales increase from right to left.

S & T scales.

I am using a Hemmi Bamboo with A, B, CI, C, D, K, S & T.

Multiplication

2.2 × 3.5

Slide C rightward, to align its 1 over 2.2 on D.
Slide the cursor to 3.5, the result will be on D as 7.7.

3.2 × 4.6

Trying to slide the cursor toward 4.6 will reach the end of the scale, we must use the inverted CI scale.

Slide CI leftward, to align its 1 over 3.2 on D.
Slide the cursor to 4.6, the result will be on D as 1.47, mul 10.

Division

3.2 / 4.6

Slide cursor to 3.2 on D.
Slide C leftward to 4.6 to align with cursor.
Slide cursor to nearest 1 on C, the result will be D as 6.9, div 10.

Square

4.0²

Slide cursor to 4.0 on C.
The result will be on B as 16.

Sin

sin(25)

Slide to 25 on S, on the backface on Hemmi Bamboo.
The result will be on B as 42.

Buzz Aldrin in space with a N600-ES slide rule

Reference

`A`	x²	square	1 to 100	On body. Two log cycles at half the scale of C/D.
`B`	x²	square	1 to 100	On slider. Two log cycles at half the scale of C/D.
`CI`	1/x	reciprocal C	1/0.1 to 1/1.0	On slider. C scale in reverse direction.
`C`	x	fundamental scale	1 to 10	On slider.
`D`	x	fundamental scale	1 to 10	On body.
`K`	x³	cube	1 to 1000	Three cycles at one third the scale of D.
`S`	sin(x)	sin	sin(5.74°) to sin(90°)	On backface, above.
`T`	tan(x)	tangent	tan(45°) to tan(84.3°)	On backface, below.

incoming: paper computing 2022