Akallabêth wrote:‘This was the beginning of that people that in the Grey-elven speech are called the Dúnedain: the Númenóreans, Kings among Men. But they did not thus escape from the doom of death that Ilúvatar had set upon all Mankind, and they were mortal still, though their years were long, and they knew no sickness, ere the shadow fell upon them. Therefore they grew wise and glorious, and in all things more like to the Firstborn than any other of the kindreds of Men; and they were tall, taller than the tallest of the sons of Middle-earth; and the light of their eyes was like the bright stars.’
So some general descriptions, noting their great height, long span of years and seeming immunity to disease; as it says they became more like Elves then men. There are though more specific indications of these attributes though.
The Return of the King, Appendix A wrote:‘For though a long span of life had been granted to them, in the beginning thrice that of lesser Men, they must remain mortal, since the Valar were not permitted to take from them the Gift of Men (or the Doom of Men, as it was afterwards called).’
Though Tolkien seemed to waver about how long the Númenóreans lived, a span of three times that of normal Men is the most common figure he gives. The Line of Elros, the Kings of Númenor, was slightly longer, around four hundred years until their decline.
A Description of Númenor wrote:‘In Númenor all journeyed from place to place on horseback; for in riding the Númenóreans, both men and women, took delight, and all the people of the land loved horses, treating them honourably and housing them nobly. They were trained to hear and answer calls from a great distance, and it is said in old tales that where there was great love between men and women and their favourite steeds they could be summoned at need by thought alone.’
This ability to summon their steeds with at a thought is very similar to Gandalf summoning Shadowfax with his thoughts, and since they are described as becoming "elvish" it's possible they did develop some form of telepathy, something common among the high-born at least.
Disaster of the Gladden Fields wrote:‘The Númenóreans in their own land possessed horses, which they esteemed. But they did not use them in war; for all their wars were overseas. Also they were of great stature and strength, and their fully-equipped soldiers were accustomed to bear heavy armour and weapons. ’
The text speaks for itself, part of the reason the Númenóreans had no cavalry was indeed due to their size and strength and ability to carry heavy loads.
Disaster of the Gladden Fields wrote:‘Measures of distance are converted as nearly as possible into modern terms. ‘League’ is used because it was the longest measurement of distance: in Númenórean reckoning (which was decimal) five thousand rangar (full paces) made a lár, which was very nearly three of our miles.’
Defining the distances of a 'Númenórean' league is important, since it has much to do with their endurance.
Disaster of the Gladden Fields wrote:‘The journey was probably at least three hundred and eight leagues as marched; but the soldiers of the Dúnedain, tall men of great strength and endurance, were accustomed to move fully-armed at eight leagues a day ‘with ease’: when they went in eight spells of a league, with short breaks at the end of each league, and one hour near midday. This made a ‘march’ of about ten and a half hours, in which they were walking eight hours. This pace they could maintain for long periods with adequate provision. In hast they could move much faster, at twelve leagues a day (or in great need more), but for shorter periods.’
So they're capable of marching twenty-four miles in a day at an easy pace while fully armored, or thirty-six plus miles for a forced march. For comparison, modern US Army doctrine has foot infantry covering an average of twenty miles while marching.
Disaster of the Gladden Fields wrote:‘Thus two ragnar was often called ‘man-high’, which at thirty-eight inches gives an average height of six feet four inches; but this was at a later date, when the stature of the Dúnedain appears to have decreased, and also was not intended to be an accurate statement of the observed average of male height among them...'
Though it obviously isn't an accurate measurement, it does give an indication of their height, which had actually shrunk during their decline.
Disaster of the Gladden Fields wrote:‘..the Hobbits of the Shire were in height between three and four feet, never less and seldom more. They did not of course call themselves Halflings; this was the Númenórean name for them. It evidently referred to their height in comparison with Númenórean men, and was approximately accurate when given.’
Here their height is given in more general terms, between six and eight feet tall, also apparently during their decline.
Disaster of the Gladden Fields wrote:‘First they let fly a hail of arrows, and then suddenly with a great shout they did as Isildur would have done, and hurled a great mass of their chief warriors down the last slope against the Dúnedain, expecting to break up their shield-wall. But it stood firm. The arrows had been unavailing against the Númenórean armour. The great Men towered above the tallest Orcs, and their swords and spears far outreached the weapons of their enemies. The onslaught faltered, broke, and retreated, leaving the defenders little harmed, unshaken, behind piles of fallen Orcs.’
There is no average height for Orcs (so far as I know) but the largest of Orcs tend to be as tall as Men, and the Númenóreans "tower" over them.
Disaster of the Gladden Fields wrote:‘[Isildur] was a man of strength and endurance that few even of the Dúnedain of that age could equal…’
An exact example of this came be seen when he was finally persuaded to flee the battle of the Gladden Fields and made his way towards the Anduin:
Disaster of the Gladden Fields wrote:‘Seven leagues or more from the place of battle. Night had fallen when he fled; he reached the Anduin at midnight or near it.’
Since the battle took place in October, assuming the sun set around six in the afternoon, Isildur ran twenty-one miles in a little under six hours while fully armed and armored over uneven ground and after having fought for several hours. The fastest marathon runners cover a slightly longer distance in a third of that time, but that's after being well rested, over nice paved roads wearing very little to weigh them down.
Disaster of the Gladden Fields wrote:‘Elendil was said to be ‘more than man-high by nearly half a ranga’; but he was accounted the tallest of all the Númenóreans who escaped the Downfall [and was indeed generally known as Elendil the Tall].’
That leaves Elendil just an inch short of eight feet tall, again gives a good upper limit for the height of Númenóreans during their decline.
Disaster of the Gladden Fields wrote:‘Though it was a long journey, each of the Dúnedain carried in a sealed wallet on his belt a small phial of cordial and wafers of a waybread that would sustain life in him for many days – not indeed the miruvor or the lembas of the Eldar, but like them, for the medicine and other arts of Númenor were potent and not yet forgotten.’
Quite apparent, Númenóreans were almost as good as the Elves when it came to making things.
A Description of Númenor wrote:‘In later days, in the wars upon Middle-earth, it was the bows of the Númenóreans that were most greatly feared. ‘The Men of the Sea’, it was said, ‘send before them a great cloud, as a rain turned to serpents, or a black hail tipped with steel’; and in those days the great cohorts of the King’s Archers used bows made of hollow steel, with black-feathered arrows a full ell long from point to notch.’
No range given, but the unique construction material is noted, and an ell is almost four feet long; many medieval war arrows were two and a half to three feet long.
Fog on the Barrow-Downs wrote:‘For each of the hobbits he chose a dagger, long, leaf-shaped, and keen, of marvelous workmanship, damasked with serpent-forms in red and gold. They gleamed as he drew them from their black sheaths, wrought of some strange metal, light and strong, and set with many fiery stones. Whether by some virtue of these sheaths or because of the spell that lay on the mound, the blades seemed untouched by time, unrusted, sharp, glittering in the sun.’
Introduction of the Barrow-blades, aka the blades of Westerness, the work of the survivors of Númenor. The possibility of their sheaths being magically enchanted is raised as well.
A Knife in the Dark wrote:‘Desperate, [Frodo] drew his own sword, and it seemed to him that it flickered red, as if it was a firebrand. Two of the [Ringwraiths] halted.’
Frodo while in the 'wraith world' draws his sword. Normal swords don't glow when viewed in this realm, nor do they usually give pause to Nazgûl. They at least notice it is a magical blade meant to harm them.
The Departure of Boromir wrote:‘He picked out from the pile of grim weapons two knives, leaf-bladed, damasked in gold and red; and searching further he found also the sheaths, black, set with small red gems. “No orc-tools these!” he said. “They were borne by the hobbits. Doubtless the Orcs despoiled them, but feared to keep the knives, knowing them for what they are: work of Westernesse, wound with spells for the bane of Mordor.”’
Aragorn and the Orcs recognize that these blades are magical and designed specifically to be used against the servants of Sauron.
Flotsam and Jetsam wrote:‘“Well!” said Merry. “I never expected to see those again! I marked a few orcs with mine; but Uglúk took them from us. How he glared! At first I thought he was going to stab me, but he threw the things away as if they burned him.”’
Besides Ringwraiths, their effect can potentially apply to Orcs too. This ability to cause pain is something seen in artifacts made by Elves, from whom the Númenóreans learned a great deal.
The Battle of the Pelennor Fields wrote:‘Then he looked for his sword that he had let fall; for even as he struck his blow his arm was numbed, and now he could only use his left hand. And behold! there lay his weapon, but the blade was smoking like a dry branch that had been thrust in a fire; and as he watched it, it writhed and withered and was consumed.
So passed the sword of the Barrow-downs, work of Westernesse. But glad would he have been to know its fate who wrought it slowly long ago in the North-kingdom when the Dunedain were young, and chief among their foes was the dread realm of Angmar and its sorcerer king. No other blade, not though mightier hands had wielded it, would have dealt that foe a wound so bitter, cleaving the undead flesh, breaking the spell that knit his unseen sinews to his will.’
The effects of a wraith being stabbed by one of these blades is explained. As noted elsewhere, the life of the Ringwraiths are bound to their Rings, which is why even getting hit by a flash flood doesn't kill them. A possible theory then is that the spells cast upon the blade breaks the link between wraith and ring, making it possible for their life to be permanently killed, as was the case here with the Witch-King.
The Black Gate Opens wrote:‘He drew his sword and looked at it, and the intertwining shapes of red and gold; and the flowing characters of Numenor glinted like fire upon the blade....
At Pippin's side Beregond was stunned and overborne, and he fell; and the great troll-chief that smote him down bent over him, reaching out a clutching claw; for these fell creatures would bite the throats of those that they threw down.
Then Pippin stabbed upwards, and the written blade of Westernesse pierced through the hide and went deep into the vitals of the troll, and his black blood came gushing out. He toppled forward and came crashing down like a falling rock, burying those beneath them. Blackness and stench and crushing pain came upon Pippin, and his mind fell away into a great darkness.’
It's very hard to pierce Troll skin; when Boromir tried with his steel sword in Moria, it bounced off chipped, while the Elven dagger Sting was able to pierce the same troll easily. However, as noted in Shelob's entry the same blade failed to cut through her web as easily as Sting did, making it clear they're at least below the level of craftsmanship that went into Sting.
Flotsam and Jetsam wrote:‘“Many of the Ents were hurling themselves against the Orthanc-rock; but that defeated them. It was very smooth and hard. Some wizardry is in it, perhaps, older and stronger then Saruman’s. Anyway they could not get a grip on it, or make a crack in it; and they were bruising and wounding themselves against it.”’
The Siege of Gondor wrote:‘At first men laughed and did not greatly fear such devices. For the main wall of the City was of great height and marvelous thickness, built ere the power and craft of Númenor waned in exile; and its outward face was like to the Tower of Orthanc, hard and dark and smooth, unconquerable by steel or fire, unbreakable except by some convulsion that would rend the very earth on which it stood.’
The masonry skills of Númenor are of excellent quality. Ents that go through normal stone like breadcrumbs are completely defeated by it, and even the explosive bombs of Mordor would be useless against it. As noted, only the a force that would disrupt the ground it stood on could break it, but in Minas Tirith's case the city was built on the Hill of Guard, a foothill of Mt. Mindolluin, which means having to go through solid rock.
The Great River wrote:‘“Behold Tol Brandir!” said Aragorn, pointing south to the tall peak. “Upon the left stands Amon Lhaw, and upon the right is Amon Hen, the Hills of Hearing and of Sight. In the days of the great kings there were high seats upon them, and watch was kept there.”
Interesting pieces of masonry left behind by the Númenóreans, probably during the reign of, if not Elendil and his sons themselves, then shortly thereafter. They appear modeled after the thrones of Manwé and Varda, their ability to see and hear far respectively. Though the Hill of Hearing is left without a description, it most likely has the same structure and ability as the Hill of Seeing:
The Breaking of the Fellowship wrote:‘Soon [Frodo] came out alone on the summit of Amon Hen, and halted, gasping for breath. He saw as through a mist a wide flat circle, paved with mighty flags, and surrounded with a crumbling battlement; and in the middle, upon four carven pillars, was a high seat, reached by a stair of many steps. Up he went and sat upon the ancient chair, feeling like a lost child that had clambered upon the throne of mountain-kings.
At first he could see little. He seemed to be in a world of mist in which there were only shadows: the Ring was upon him. Then here and there the mist gave way and he saw many visions: small and clear as if they were under his eyes upon a table, and yet remote. There was no sound, only bright living images. The world seemed to have shrunk and fallen silent. He was sitting upon the Seat of Seeing, on Amon Hen, the Hill of the Eye of the Men of Númenor. Eastward he looked into wide uncharted lands, nameless plains, and forests unexplored. Northward he looked, and the Great River lay like a ribbon beneath him, and the Misty Mountains stood small and hard as broken teeth. Westward he looked and saw the broad pastures of Rohan; and Orthanc, the pinnacle of Isengard, like a black spike. Southward he looked, and below his very feet the Great River curled like a toppling wave and plunged over the falls of Rauros into a foaming pit; a glimmering rainbow played upon the fume. And Ethir Anduin he saw, the mighty delta of the River, and myriads of sea-bird whirling like a white dust in the sun, and beneath them a green and silver sea, rippling in endless lines.
But everywhere he looked he saw the signs of war. The Misty Mountains were crawling like anthills: orcs were issuing out of a thousand holes. Under the boughs of Mirkwood there was deadly strife of Elves and Men and fell beasts. The land of the Beornings was aflame; a cloud was over Moria; smoke rose on the borders of Lórien.
Horsemen were galloping on the grass of Rohan; wolves poured from Isengard. From the havens of Harad ships of war put out to sea; and out of the East Men were moving endlessly: swordsmen, spearmen, bowmen upon horses, chariots of chieftains and laden wains. All the power of the Dark Lord was in motion. Then turning south again he beheld Minas Tirith. Far away it seemed, and beautiful: white-walled, many-towered, proud and fair upon its mountain-seat; its battlements glittered with steel, and its turrets were bright with many banners. Hope leaped in his heart. But against Minas Tirith was set another fortress, greater and more strong. Thither, eastward, unwilling his eyes were drawn. It passed the ruined bridges of Osgiliath, the grinning gates of Minas Morgul, and the haunted Mountains, and it looked upon Gorgoroth, the valley of terror in the land of Mordor. Darkness lay there under the Sun. Fire glowed amid the smoke. Mount Doom was burning, and a great reek rising. Then at last his gaze was held: wall upon wall, battlement upon battlement, black, immeasurably strong, mountain of iron, gate of steel, tower of adamant, he saw it: Barad-dûr, Fortress of Sauron. All hope left him.’
Frodo is seeing, in very precise detail, events that are taking place literally hundreds of miles away, thousands if he's looking all the way into Harad. This would prove a great advantage to the Númenóreans, however they already had all seven Seeing Stones at this point as well, each with the exact same power, so it would seem to be redundant. However, the Seeing Stones were even at this time kept secret, and their primary use had always been communication between each other, with usually a strong will required to direct it to see some other part of the world. Plus, while you could see, you could not hear through the Palantír
. Working in conjunction, the Seats of Seeing and Hearing would give the Númenóreans a tremendous intelligence advantage over an opponent. While they couldn't make any more Palantír
, they were probably able to study its effects and replicate them for the Seats. However they didn't always work:
The Departure of Boromir wrote:‘Aragorn hesitated. He desired to go to the high seat himself, hoping to see there something that would guide him in his perplexities; but time was pressing. Suddenly he leaped forward, and ran to the summit, across the great flag-stones, and up the steps. Then sitting in the high seat he looked out. But the sun seemed darkened, and the world dim and remote. He turned from the North back again to North, and saw nothing save the distant hills, unless it were that far away he could see again a great bird like an eagle high in the air, descending slowly in wide circles down towards the earth.’
Why it doesn't work for Aragorn I believe has a lot to do with Sauron. In the paragraphs immediately following the previous description he attempts to dominate Frodo's mind and has a mental shoving match with Gandalf (see respective entries). While Gandalf succeeded, Sauron probably still maintained his presence in the area, and it is known that he was the ability to diminish the powers of others and to hide areas from farseeing abilities. This then he used to keep anyone else from using the Seats, at least while they were still in the area.