What I think it says is "Item I give to my son Robert a silver gilt bowl with a cover covered with a silver gilt night time crescent moon". Pernox, pernoctis is an adjective meaning night and I think the word after is something like lunacio, to do with moon.
Where it says Rector, you would expect after that, "of this parish" or somesuch, but I can't see parish. I'm still looking at the last few lines, cb