Magic Rain Stone.
Reading edition
The Indian magi, who are to invoke Yo He Wah, and meditate with the supreme holy fire that he may give seasonable rains, have a transparent stone of supposed great power in assisting to bring down the rain when it is put in a basin of water. It is reputed to possess divine virtue; it would suffer decay, they assert, were it even seen by their own laity; but if by foreigners, it would be utterly despoiled of its divine communicative power.