Question: Who was the Scottish mathematician, physicist and astronomer who is credited for introducing "natural" logarithmic function?

Context articles: James Gregory (mathematician)
Andrew Mackay (mathematician)
Logarithmically convex function
John Napier
John Napier (disambiguation)
Oversampled binary image sensor
James Hume (mathematician)
Common logarithm
Napierian logarithm
Logarithmic units

James Gregory FRS (November 1638 – October 1675) was a Scottish mathematician and astronomer.
 His surname is sometimes spelt as Gregorie, the original Scottish spelling.
 He described an early practical design for the reflecting telescope – the Gregorian telescope – and made advances in trigonometry, discovering infinite series representations for several trigonometric functions.
Dr Andrew Mackay FRSE LLD (1760–1809) was a Scottish mathematician and astronomer, known as a teacher of navigation.
In mathematics, a function "f" defined on a convex subset of a real vector space and taking positive values is said to be logarithmically convex or superconvex if formula_1, the composition of the logarithmic function with "f", is a convex function.
 In effect the logarithm drastically slows down the growth of the original function formula_2, so if the composition still retains the convexity property, this must mean that the original function formula_2 was 'really convex' to begin with, hence the term superconvex.
John Napier of Merchiston ( ; 1 February, 1550 – 4 April 1617); also signed as Neper, Nepair; nicknamed Marvellous Merchiston) was a Scottish landowner known as a mathematician, physicist, and astronomer.
 He was the 8th Laird of Merchiston.
 His Latinized name was Ioannes Neper.
John Napier (1550–1617) was a Scottish mathematician, physicist and astronomer.
An oversampled binary image sensor is a new image sensor that is reminiscent of traditional photographic film.
 Each pixel in the sensor has a binary response, giving only a one-bit quantized measurement of the local light intensity.
 The response function of the image sensor is non-linear and similar to a logarithmic function, which makes the sensor suitable for high dynamic range imaging.
James Hume (fl.
 1639) was a Scottish mathematician.
 He is given credit for introducing the modern exponential notation, along with René Descartes.
In mathematics, the common logarithm is the logarithm with base 10.
 It is also known as the decadic logarithm and also as the decimal logarithm, named after its base, or Briggsian logarithm, after Henry Briggs, an English mathematician who pioneered its use, as well as "standard logarithm".
 Historically, it was known as "logarithmus decimalis" or "logarithmus decadis".
 It is indicated by log("x"), or sometimes Log("x") with a capital "L" (however, this notation is ambiguous since it can also mean the complex natural logarithmic multi-valued function).
 On calculators it is usually "log", but mathematicians usually mean natural logarithm (logarithm with base e ≈ 2.71828) rather than common logarithm when they write "log".
 To mitigate this ambiguity the ISO 80000 specification recommends that log("x") should be written lg ("x") and log("x") should be ln ("x").
The term Napierian logarithm or Naperian logarithm, named after John Napier, is often used to mean the natural logarithm.
 Napier did not introduce this "natural" logarithmic function, although it is named after him.
 However, if it is taken to mean the "logarithms" as originally produced by Napier, it is a function given by (in terms of the modern logarithm):
A logarithmic unit is an abstract mathematical unit that can be used to express any quantity (physical or mathematical) that is defined on a logarithmic scale, that is, as being proportional to the value of a logarithm function.
 Here, a given logarithmic unit will be denoted using the notation [log "n"], where "n" is a positive real number, and [log ] here denotes the indefinite logarithm function formula_1.