Buttons and lines

[Tribuno]

Hello 

I'm having a look to "Dress Regulations for the Army" (1911) and in the section that deal with buttons measures I found that:

BUTTONS 

Buttons-—Buttons are of the following sizes:—

Large            35 to 40 lines (Hussars 32 lines).

Medium               30 to 34 .

Small                     24 to 29 .

Gorget                  20 lines

I was looking for old imperial british lenght units and found that a line=0.2116667 cm.

http://www.convert-me.com/en/convert/units/length/length.line.en.html

then a gorget button would be 4,2334 cm

as I found it too big I go on searching  and:

http://en.wikipedia.org/wiki/Ligne

With this conversion 1 line=0.025 inches=0.1 cm

Then a gorget button= 2 cm that likes more reasonable as you can see.

The question is: What is the real  measurement of a line in inches or centimeters when you are talking about buttons in those regulations?

Thanks and regards.

[auchonvillerssomme]

Line ... In ... mm

14-line 0.362 9.2mm

16-line 0.413 10.5mm

18-line 0.457 11.6mm

20-line 0.492 12.5mm

21-line 0.531 13.5mm

22-line 0.559 14.2mm

23-line 0.583 14.8mm

24-line 0.590 15.0mm

27-line 0.661 16.8mm

28-line 0.701 17.8mm

30-line 0.748 19.0mm

32-line 0.807 20.5mm

34-line 0.846 21.5mm

36-line 0.902 22.9mm

40-line 1.000 25.4mm

60-line 1.500 38.1mm

80-line 2.000 50.8mm

120-line 3.000 7 6.2mm

[Tribuno]

Line ... In ... mm

14-line 0.362 9.2mm

16-line 0.413 10.5mm

18-line 0.457 11.6mm

20-line 0.492 12.5mm

21-line 0.531 13.5mm

22-line 0.559 14.2mm

23-line 0.583 14.8mm

24-line 0.590 15.0mm

27-line 0.661 16.8mm

28-line 0.701 17.8mm

30-line 0.748 19.0mm

32-line 0.807 20.5mm

34-line 0.846 21.5mm

36-line 0.902 22.9mm

40-line 1.000 25.4mm

60-line 1.500 38.1mm

80-line 2.000 50.8mm

120-line 3.000 7 6.2mm

Thanks auchonvillerssomme