08-13-2008, 10:24 PM
The CHORD is the distance across the arc described by the face of the shield.
The diameter of a circle is a CHORD. Its the longest chord on a circle.
http://rlqm.com/LEG.XIV.Scutum.Info/chord.jpg
The depth of the arc..., a line perpendicular at the center of the chord to the arc is called the SAGITTA (The same line is called the radius if its on the chord called the diameter)
Most new LEG IX scutums have a SAGITTA of 7 inches. Some old IX luan shields had a sagitta of 4.5".
The Final report on Dura shows a site drawing that gives the famous DURA scutum a 9" sagitta, but that is in doubt as the scutum was in crushed and in 13 pieces.
Two shields with the same chord but having different face lengths will have different sagitta.
Bend a 34" shield into a 26" chord
Bend a 30" shield into a 26" chord
.. two different sagitta.
Geometry...
Hibernicus
The diameter of a circle is a CHORD. Its the longest chord on a circle.
http://rlqm.com/LEG.XIV.Scutum.Info/chord.jpg
The depth of the arc..., a line perpendicular at the center of the chord to the arc is called the SAGITTA (The same line is called the radius if its on the chord called the diameter)
Most new LEG IX scutums have a SAGITTA of 7 inches. Some old IX luan shields had a sagitta of 4.5".
The Final report on Dura shows a site drawing that gives the famous DURA scutum a 9" sagitta, but that is in doubt as the scutum was in crushed and in 13 pieces.
Two shields with the same chord but having different face lengths will have different sagitta.
Bend a 34" shield into a 26" chord
Bend a 30" shield into a 26" chord
.. two different sagitta.
Geometry...
Hibernicus
Hibernicus
LEGIO IX HISPANA, USA
You cannot dig ditches in a toga!
[url:194jujcw]http://www.legio-ix-hispana.org[/url]
A nationwide club with chapters across N America
LEGIO IX HISPANA, USA
You cannot dig ditches in a toga!
[url:194jujcw]http://www.legio-ix-hispana.org[/url]
A nationwide club with chapters across N America
