Sweatology

Like the finish line of a long road race, the Times Square subway platform one recent hot afternoon was a study in wet humanity, from drenched (a large woman in shorts and a skimpy, sweat-splotched top, flushed and vigorously fanning herself), to barely bedewed (an elderly man in a suit and tie calmly reading his paper).

Who would believe that every sufferer had the same model of personal air-conditioner operating at full blast?

Sweat is our interior coolant, part of a uniquely human biologic machine. The machine drips and occasionally stalls: long waits on torpid platforms can inspire glum reflections on how it will hold up as the planet heats up. But experts counsel optimism: the system is sturdy, adjustable and even reproducible by engineers working to make our future sweaty selves more comfortable.