在Silmarillion里, Meglin的叛变说的比较简单, 又加上童年的遭遇,暗恋未果, 使他不那麽照人恨,
"梅格林时常带著少数几名跟随者离开山岭到外地去，王并不知道他的命令遭到了违抗。因此，事
情就如命中注定的发生了，梅格林被半兽人俘虏，带到了安格班。梅格林既非孱弱之辈，也不是懦
夫，但是他在那里所遭受到的酷刑，确实削弱了他的心智；最後，他以揭发贡多林的确实位置以及
可循的进攻路线，向魔苟斯换取他个人的性命与自由。魔苟斯大喜若狂，承诺将来把城攻下後，
梅格林可代他治理贡多林，并且占有伊缀尔 凯勒布琳朵为妻。对伊缀尔的渴望与对图尔的憎恨，
令梅格林更加轻易地做出背信忘义之举，这是远古历史中最臭名昭彰的背叛。"
不过, 读了Lost Tales里的仔细的描写. 孰可谅, .孰不可谅.
Fall of Gondoling 是要从他的叛变开始的, 不过我too愤愤to翻译了. 就贴一下, 算个开头.
Now it so chanced that not long after Meglin went to the hills for
the getting of ore, and straying in the mountains alone was taken
by some of the Orcs prowling there, and they would do him evil
and terrible hurt, knowing him to be a man of the Gondothlim.
This was however unknown of Tuor's watchers. But evil came
into the heart of Meglin, and he said to his captors: "Know then
that I am Meglin son of Eol who had to wife Isfin sister of Turgon
king of the Gondothlim." But they said: "What is that to us?" And
Meglin answered: "Much is it to you; for if you slay me, be it
speedy or slow, ye will lose great tidings concerning the city of
Gondolin that your master would rejoice to hear." Then the Orcs
stayed their hands, and said they would give him life if the matters
he opened to them seemed to merit that; and Meglin told them of
all the fashion of that plain and city, of its walls and their height
and thickness, and the valour of its gates; of the host of men at
arms who now obeyed Turgon he spake, and the countless hoard
of weapons gathered for their equipment, of the engines of war
and the venomous fires.
Then the Orcs were wroth, and having heard these matters
were yet for slaying him there and then as one who impudently
enlarged the power of his miserable folk to the mockery of the
great might and puissance of Melko; but Meglin catching at a
straw said: "Think ye not that ye would rather pleasure your
master if ye bore to his feet so noble a captive, that he might hear
my tidings of himself and judge of their verity?"
Now this seemed good to the Orcs, and they returned from the
mountains about Gondolin to the Hills of Iron and the dark halls
of Melko; thither they haled Meglin with them, and now was he in
a sore dread. But when he knelt before the black throne of Melko
in terror of the grimness of the shapes about him, of the wolves
that sat beneath that chair and of the adders that twined about its
legs, Melko bade him speak. Then told he those tidings, and
Melko hearkening spake very fair to him, that the insolence of his
heart in great measure returned.
Now the end of this was that Melko aided by the cunning of
Meglin devised a plan for the overthrow of Gondolin. For
this Meglin's reward was to be a great captaincy among the Orcs --
yet Melko purposed not in his heart to fulfil such a promise -- but
Tuor and Earendel should Melko burn, and Idril be given to
Meglin's arms -- and such promises was that evil one fain to
redeem. Yet as meed of treachery did Melko threaten Meglin with
the torment of the Balrogs. Now these were demons with whips of
flame and claws of steel by whom he tormented those of the
Noldoli who durst withstand him in anything -- and the Eldar have
called them Malkarauki. But the rede that Meglin gave to Melko
was that not all the host of the Orcs nor the Balrogs in their
fierceness might by assault or siege hope ever to overthrow the
walls and gates of Gondolin even if they availed to win unto
the plain without. Therefore he counselled Melko to devise out
of his sorceries a succour for his warriors in their endeavour.
From the greatness of his wealth of metals and his powers of fire he
bid him make beasts like snakes and dragons of irresistible might
that should overcreep the Encircling Hills and lap that plain and
its fair city in flame and death.
