After Gibbs, one the most distinguished [American scientists] was Langley, of the Smithsonian. ... He had the physicist's heinous fault of professing to know nothing between flashes of intense perception. ... Rigidly denying himself the amusement of philosophy, which consists chiefly in suggesting unintelligible answers to insoluble problems, and liked to wander past them in a courteous temper, even bowing to them distantly as though recognizing their existence, while doubting their respectibility.