Sauron's first demise.

[Túroch]

I was rereading the Silmarillion yesterday and got to the part about the sinking of Numenor and a though struck me. We all know why Sauron survived his destuction and the hands of the last alliance, the ring endured and because he put a large part of his power into it he also endured. But what about when he perished during the sinking of Numenor. How could he of survived the destruction. Where was the ring then? He couldn't of had it on him when Numenor sunk or it would have been lost. Would he of left it behind him though?

Also something else. After the destuction of his physical form the book said that "he wrought himself a new guise, an image of malicee andhatred made visible; and the Eye of Sauron the Terrible few could endure." So is the nebulous eye his new form? If so what from was he in when his hand was cut off from Isildur. The Eye of Sauron to my understanding is not a "real" physical from but merely a visible guise for his spirit.