This quote highlights the difference the narrator finds between the perfect lives of nine bachelors (well-to-do young lawyers) he witnesses at a dinner he attends in London and the lot of the young unmarried women working in a hellish New England paper factory.
The dinner he attends in London in a comfortable apartment near the Temple, the London law courts, is described in detail. The men dine on oxtail soup and roast beef, mutton, and fowl—all meats that would have been costly—along with sherry, wine, and port. The cost of the meal, out of reach of the working classes, reveals the affluence enjoyed by these men. The narrator observes that for the men it:
It was the very perfection of quiet absorption of good living, good drinking, good feeling, and good talk. We were a band of brothers.
However, it becomes apparent in the second story, where we find the quote about the snowed upon "sepulcher" or tomb of the paper mill, that the bachelor men are oblivious to the labors of the young women that make their delightful lives possible. The narrator finds that the women work in dismal and dangerous conditions. If the men dine in a "paradise," the women slave in a "Tartarus" or a prison of torment.
In the quote, the speaker has not yet entered into the paper factory, but is simply approaching it from the outside. Even as he comes up to it, he can perceive that the factory represents the "counterpoint" or opposite of the lawyers' experience. Even on the outside it looks like a tomb because it is covered in snow and frost. The whiteness represents evil (as it does in Moby Dick). The building's wintry color symbolizes the bleached bones of suffering and death. The cheap paper the affluent bachelor lawyers use is produced on the backs of underpaid and overworked young women:
For our factory here, we will not have married women; they are apt to be off-and-on too much. We want none but steady workers: twelve hours to the day, day after day, through the three hundred and sixty-five days, excepting Sundays, Thanksgiving and Fastdays.