Eventually the following lessons framed themselves in my head--some of them quite new, some of them supplementing those four I had already learnt:
5. With modern rifles, to guard a drift or locality does _not_ necessitate sitting on top of it (as if it could be picked up and carried away), unless the locality is suitable to hold for other and defensive reasons. It may even be much better to take up your defensive position some way from the spot, and so away from concealed ground, which enables the enemy to crawl up to very close range, concealed and unperceived, and to fire from cover which hides them even when shooting. It would be better, if possible, to have the enemy in the open, or to have what is called a clear "field of fire."
A non-bullet proof parapet or shelter which is visible serves merely to attract bullets instead of keeping them out--the proof-thickness can be easily tested practically.
When fired at by an enemy at close range from nearly all round, a low parapet and shallow trench are not of much use, as what bullets do not hit the defenders on one side hit those on another.
6. It is _not_ enough to keep strange men of the enemy's breed away from your actual defences, letting them go free to warn their friends of your existence and whereabouts--even though they do not know the details of your defences. It would be very much better to gather in all such strangers and kindly, but firmly, to take care of them, so that they should not be under temptation to impart any knowledge they may have obtained. "Another way," as the cookery book says, more economical in lives, would be as follows: Gather and warmly greet a sufficiency of strangers. Stuff well with chestnuts as to the large force about to join you in a few hours; garnish with corroborative detail, and season according to taste with whiskey or tobacco. This will very likely be sufficient for the nearest commando. Probable cost--some heavy and glib lying, but no lives will be expended.
7. It is not business to allow lazy black men (even though they be brothers and neutrals) to sit and pick their teeth outside their kraals whilst tired white men are breaking their hearts trying to do heavy labor in short time. It is more the duty of a Christian soldier to teach the dusky neutral the dignity of labor, and to keep him under guard, to prevent his going away to talk about it.