\"Celtic\" military technology and the Romans

[Renatus]

Plus Julian uses the metaphor 'web' for mail, would he have resisted the use of fish or snake metaphors if he were describing scale armour?

This is false reasoning. You cannot base any argument upon what an ancient author might have written, had he thought of it.

The Dura rectangles are small when compared with the parts of a muscle cuirass. Then there is the problem of unequal division of protection if what you say is true. Why go to the expense of giving the limbs intricate and expensive armour, when the more vital torso is given merely the same level of defence as most troops would wear - it just doesn't make sense.

A horse is small when compared with an elephant but it is not a small animal. The Dura rectangles are not small. In fact, the first impression they give is how large they are. And they do not cover the shoulders and breast, as Julian's 'small pieces' do. Further, the Dura graffito has just the anomaly that you complain of; the arms and legs are protected by articulated armour but the breast is protected by scale or, possibly, mail.