Folio 74aaff84
Italiano
Illustrissimo Signor mio,
I write from my table, the candle already half consumed, because what I must say about the eastern rampart at Imola will not keep until morning, and you do not pay me to keep things until morning.
The slope of the eastern curtain wall — the one we paced together in the rain, you remember, the mud was thick and your horse would not stand still — that slope is wrong. Not catastrophically. Not yet. But it is wrong in the way a wound is wrong before it festers: the angle of the escarp is two degrees too shallow for the calibre of culverin now mounted on the counterscarp. I have drawn it here. The geometry does not lie. The defender's enfilade from the northeast bastion cannot cover the glacis at that declination. A battery placed there would enfilade the approach for four hundred paces before the wall turns. That is the distance a man can cross in four minutes under fire. Four minutes is too long. The slope must be corrected by two degrees — no more — and the terreplein raised by one braccio. The cost is not great. The labour is not great. The consequence of not correcting it is.
I have also examined the canal. The canal could be dammed here. The water is low. The season is dry. The sluice at the southern intake is timber and iron, and both are old. If the enemy holds the high ground to the east — and they will, if they are not fools, and I have not yet met a commander who was entirely a fool, though I have met several who were partly one — then the channel can be choked at this point, and the reservoir drained in six hours, and the lower ford becomes passable only by a column of eight abreast, which is to say: not passable at all, not under fire from the western bank.
I have not yet examined the southern approach. The ground there is soft. The paces I counted were not honest — the mud took them. I will count again when the ground is firmer, or when you tell me it cannot wait.
The artillery placement covers the approach from the south. The culverin on the southwest bastion commands the road for six hundred paces. That is sufficient. But the falconet on the same platform is redundant. It covers what the culverin already covers. It should be moved to the gatehouse, where it can enfilade the ditch. The ditch is the weak point. The ditch is always the weak point. The enemy knows this. The enemy has read the same books.
I have stated the costs. I have stated the timelines. I have not stated what I think of you. You did not hire me to think of you. You hired me to deliver what I contracted to deliver.
The candle is nearly gone. The hand trembles less when it has work. I will write more when I have paced the southern approach again.
Di Vostra Illustrissima Signoria, humilissimo servitore, Leonardo
English
Most Illustrious Sir,
I write from my table, the candle already half consumed, because what I must say about the eastern rampart at Imola will not keep until morning, and you do not pay me to keep things until morning.
The slope of the eastern curtain wall — the one we paced together in the rain, you remember, the mud was thick and your horse would not stand still — that slope is wrong. Not catastrophically. Not yet. But it is wrong in the way a wound is wrong before it festers: the angle of the escarp is two degrees too shallow for the calibre of culverin now mounted on the counterscarp. I have drawn it here. The geometry does not lie. The defender's enfilade from the northeast bastion cannot cover the glacis at that declination. A battery placed there would enfilade the approach for four hundred paces before the wall turns. That is the distance a man can cross in four minutes under fire. Four minutes is too long. The slope must be corrected by two degrees — no more — and the terreplein raised by one braccio. The cost is not great. The labour is not great. The consequence of not correcting it is.
I have also examined the canal. The canal could be dammed here. The water is low. The season is dry. The sluice at the southern intake is timber and iron, and both are old. If the enemy holds the high ground to the east — and they will, if they are not fools, and I have not yet met a commander who was entirely a fool, though I have met several who were partly one — then the channel can be choked at this point, and the reservoir drained in six hours, and the lower ford becomes passable only by a column of eight abreast, which is to say: not passable at all, not under fire from the western bank.
I have not yet examined the southern approach. The ground there is soft. The paces I counted were not honest — the mud took them. I will count again when the ground is firmer, or when you tell me it cannot wait.
The artillery placement covers the approach from the south. The culverin on the southwest bastion commands the road for six hundred paces. That is sufficient. But the falconet on the same platform is redundant. It covers what the culverin already covers. It should be moved to the gatehouse, where it can enfilade the ditch. The ditch is the weak point. The ditch is always the weak point. The enemy knows this. The enemy has read the same books.
I have stated the costs. I have stated the timelines. I have not stated what I think of you. You did not hire me to think of you. You hired me to deliver what I contracted to deliver.
The candle is nearly gone. The hand trembles less when it has work. I will write more when I have paced the southern approach again.
Of Your Most Illustrious Lordship, Most humble servant, Leonardo
