From the text:
“It's an alethiometer. It's one of only six that were ever made. Lyra, I urge you again: keep it private. It would be better if Mrs. Coulter didn't know about it. Your uncle—”
“But what does it do?”
“It tells you the truth. As for...
The Question and Answer section for The Golden Compass is a great resource to ask questions, find answers, and discuss the novel.
From the text:
“It's an alethiometer. It's one of only six that were ever made. Lyra, I urge you again: keep it private. It would be better if Mrs. Coulter didn't know about it. Your uncle—”
“But what does it do?”
“It tells you the truth. As for...
Lord Asriel brings slides taken on his trip to Lapland, slides of the dust falling in the area.
The college makes money because it owns enormous plots of land, on which, there are dye workd, brick kilns, forests, and atomcrom works. Each of these businesses pays large rents to the college.