In the absence of vibratory media the noises of the reef are isolated. furtive, echoless--staccato accidentals and dull dissonances out of tune with the soothing theme of the sea. Hence, when, as I wandered absorbed in an inspection of minor details, and a mellow whistle, constant but varying in volume, broke in upon my musings, it was vain to repress the thrill of excitement. A sound so foreign and incongruous also had a certain element of mystery. In a flash unsensational ponderings were displaced by a picture of a steamer in distress far away. Had I not on a similar occasion of a secret-disclosing tide heard through seven miles of insulted and sullen air the flop of an inch or so of dynamite exploded by a heartless barbarian for the illicit destruction of vivacious fish? Had I not listened with amazement to the buzz of a steamer's propeller and the throb of her engines six miles away when unaccustomed "nigger-heads" of coral showed yellow in the sun? The calm, shallow sea conveyed the sounds with marvellous fidelity and surety. Yet this unaccountable call came from a quarter whence steamers may not venture, and was I not the only whistler within a range of many miles? No steamer ever gloated or warned or appealed in so fluty a note--plaintive, slightly tremulous, nervously imploring. Alert, I tracked the strange sound along an eccentric course to its haunt, finding nothing more than the empty shell of a huge sea urchin, which in accord with a whim of the sea had floated and was now held aloft slantwise to the lips of the wind, firm in the branching tines of stag's-horn coral. A rustic pipe--giving forth a sonorous moan, now cooing and crooning, now bold and confident, and again irresolute and unschooled. Not too sure of instrumentalism, oft the note was hesitating, soliciting a compliant ear as became a modest wooer of the muses, polishing his unceremonious serenade to some, shy mermaid, or hooting at shyer silence. A new art, a rare accomplishment! So the musician was diffident, half-ashamed, half-shocked at his audacity, wholly self-conscious; earnest to please yet doubtful of the reception awaiting his untutored, artless play. Gathering courage, the breeze moistened his lips and a triumphant spasm of sound boomed out, and again the tremulous undertone prevailed. It was more than a serenade--a primitive sensation from primitive matter--a vital function, for as long, as the wind blew and until the lapping sea gurgled in its throat and its note ceased with the bursting of a bubble, there, held fixedly by living coral, the dead shell could not choose but whistle. So I left it to its wayward pipings, happy to have been the sole auditor to a purely natural, albeit mechanical, monotone. Upon such an instrument did the heavenly maid beguile the time when she was yet uncouthly young--at the hoydenish age when men also cajoled her with clicking sticks and the beating of hollow logs, and music was but a variety of noise. CHAPTER V