This poem uses the fact that the monks sent by Qin Shihuang (the "land Lord" in the second sentence should be "alchemist") went to the sea to seek immortality, to show that monasticism can't seek immortality from the outside (in that case, it is like snowflakes melting when heated), but should work hard from the heart.
The whole poem seems to tell you not to infer the future in the form of questions, but to see whether you are aggressive or passive. The result is completely in your own hands.