I cant remember who it was by, but I read on here someone's blog about how Mother's quote about the source was an elementary school riddle about how every man has a little but they always want more and the answer was time. Mother said if they found it (talking about the source)they may put it out, and if it goes out on the island, it goes out everywhere. If they manipulate too much of the time on the island, all time will stop on and off island. Jacob seemed pretty content when offering Richard eternal life (every man has a little life,or time, alotted in him). He probably knows how to tap into it w/o putting it out, which is how he seems to appear the same age in so many different years.
I think whoever wrote that original blog has a great idea, if its you let me know! If not, let me know what you think anyway!