History of the word "scales" in graphing

Question

I am curious to know who first used the term "scale" in graphing, and what exactly did they mean.

Depending on which dictionary you use, a scale can mean "a coating" or a scale can mean a device for weighing (or measuring).

The way scales are described in a Data Visualization Course I am taking, "scales" are a kind of aesthetic onto which we map our data (like "scales" on a fish); part of a theory of the "Grammar of Graphics".

On the other hand, in other classes, it has always seemed like scales are a kind of measure of weight.

My questions are:

1. Who first used this term ("scale" or "scales")?
2. Which meaning (or analogy) of "scale" were they trying to convey?
3. Also, has the meaning of "scale" (or "scales") in graphing changed over time (e.g., with the "Grammar of Graphics", and, if so, by whom?

Answer 1

There are (at least) three different English words written and pronounced “scale”.

The “scale” of a fish or reptile is a borrowing from an Old French word adopted from a Germanic form cognate with the English word “shell”.

A "scale" for weighing is originally a "bowl", borrowed from Old Norse.

“Scale” in its various mathematical usages is borrowed from Latin scala “ladder”.

These are totally different words; homonyms.

The mathematical usage goes back a long time. Just to stay with English, the Oxford English Dictionary quotes the sentence from Chaucer’s Treatise on the Astrolabe from about 1400 referenced in Gerald's answer. This is the earliest recorded use of the word in English, but it follows the example of earlier usage in French and Latin.

Answer 2

Scale

3. a graduated range of values forming a standard system for measuring or grading something

From Latin scala, ladder

For example, in Chaucer, 1391:

Next the forseide cercle of the A. b. c., vnder the cros-lyne, is Marked the skale, in Maner of 2 Squyres or elles in Manere of laddres.