I have a numeric table for artillery operations (Royal Italian Army, year 1940), in the instructions it refers to a measure of a planar angle as $32.00^{\circ\circ}$ and it seems to me that this angle is equivalent to $\pi$ radian. I had a look at https://en.wikipedia.org/wiki/Gradian but it states that $\pi$ radian is equal to 200 gradian.
Referring to the following figure, given the angles $\alpha$, $\beta$ and the distance $b$, the numeric table will give the distance $X$.
My rough translation of the interesting part of the instruction is this:
The angles $\alpha$ and $\beta$ will be measured by means of goniometers. So in each end-point of the baseline you will set up a goniometer, the direction of the goniometer is the direction of the baseline $SD$ and the orientation of the goniometer will be from $D$ to $S$. So the angle of the line-of-sight from $D$ to $S$ will be set up, in the goniometer in $D$, equal to $0.00^{\circ\circ}$ and the angle of the line-of-sight from $S$ to $D$ will be set up, in the goniometer in $S$, equal to $32.00^{\circ\circ}$.
Edit
After the answer by Christian Blatter I have found some nice pictures of the Swiss Army Compass with the "Art. ‰" scale:
The full circle is subdivided into $6400$ artillery promilles, whereby "pro mille" is latin for ${1\over1000}$. The idea behind this angle measure is that a circle of radius $1000$ m has a circumference of $$2\pi\cdot 1000\ {\rm m}=6283.2\ {\rm m}\ \approx 6400\ {\rm m}\ ,$$ so that an angle of $1$ artillery promille corresponds to $1$ m circumference at a distance of $1000$ m. One then can say that also the tangent of this angle is about ${1\over1000}$, or $1$ per thousand. This means that you can easily convert promilles deviation measured with your binoculars into distances orthogonal to the line of sight, if you know the distance to the target, or conversely, can convert the (small) angle under which you see, e.g., a telephone pole into the distance to this pole.