Answer:
The mention of the "midnight sun" and men who "moil for gold" indicates that the poem takes place during the Klondike Gold Rush in the Yukon in the late nineteenth century.
Step-by-step explanation:
This is an extract from a Robert W. Service poem called "The cremation of Sam McGee". Robert W. Service wrote many poems referring to the Yukon and the Gold Rush that took place around 1898 (late nineteenth century). This poem talks about a prospector (people who went to the Yukon to look for gold) that froze to death during one Yukon winter.
The Yukon is also known as the "land of the midnight sun" because during summer the sun doesn't set and there's light during midnight.
Thus, the mention of the "midnight sun" and men who "moil for gold" indicates that the poem takes place during the Klondike Gold Rush in the Yukon in the late nineteenth century.