"The day increased from heat to heat."

At last they were aware of an end of their visits, and of a purpose to go
down town again, and of seeking the nearest car by endless blocks of
brown-stone fronts, which with their eternal brownstone flights of steps,
and their handsome, intolerable uniformity, oppressed them like a
procession of houses trying to pass a given point and never getting by.
Upon these streets there was, seldom a soul to be seen, so that when
their ringing at a door had evoked answer, it had startled them with a
vague, sad surprise. In the distance on either hand they could see cars
and carts and wagons toiling up and down the avenues, and on the next
intersecting pavement sometimes a laborer with his jacket slung across
his shoulder, or a dog that had plainly made up his mind to go mad. Up to
the time of their getting into one of those phantasmal cars for the
return down-townwards they had kept up a show of talk in their wretched
dream; they had spoken of other hot days that they had known elsewhere;
and they had wondered that the tragical character of heat had been so
little recognized. They said that the daily New York murder might even at
that moment be somewhere taking place; and that no murder of the whole
homicidal year could have such proper circumstance; they morbidly
wondered what that day's murder would be, and in what swarming
tenement-house, or den of the assassin streets by the river-sides,--if
indeed it did not befall in some such high, close-shuttered, handsome
dwelling as those they passed, in whose twilight it would be so easy to
strike down the master and leave him undiscovered and unmourned by the
family ignorantly absent at the mountains or the seaside. They
conjectured of the horror of midsummer battles, and pictured the anguish
of shipwrecked men upon a tropical coast, and the grimy misery of
stevedores unloading shiny cargoes of anthracite coal at city docks. But
now at last, as they took seats opposite one another in the crowded car,