Final answer:
The phrase in question indicates a military unit's significant defeat or dishonorable action, impacting its reputation and honor.
Step-by-step explanation:
The phrase "Nine 'undred of is county an the Regiment's disgrace" appears to be a stylized or dialectal way of saying "Nine hundred of his county and the Regiment's disgrace." This implies that a military unit, possibly consisting of 900 men from a particular county, has suffered a significant defeat or acted in a manner that brought shame upon themselves and their regiment.
Contextually, it speaks to the consequences of military engagement and the impact of defeat or cowardice on a regiment's honor. The passages provided discuss various historical events and military strategies, but the specific phrase in question does not directly relate to them beyond the general subject of military defeat.