CHAPTER XII. APPROACHING A WORLD OF MYSTERY. Gaston Brielle, the strawberry blonde French chauffeur who piloted the big, luxurious motor car Jabez Hogg of Omaha had placed at the service of Mrs. Elvira Burton and her two charming young nieces, did not have his mind entirely concentrated upon manipulating the wheel and throttle of the car as he swung around Grant's Tomb and sped southward down the Drive. While his knowledge of English was confined to a few expletives of a profane nature and the mystic jargon of the garage, he was nevertheless thrilled by the belief that the two mademoiselles behind him were plotting some mysterious enterprise. From time to time they had unconsciously dropped their voices to the low tones commonly used by conspirators, or at least that was the way Gaston had sensed it. Along the silent roads of Central Park and Riverside Drive, where even the taxis seemed to employ their mufflers and to resort less frequently to the warning racket of their exhausts, the Frenchman had been straining his ears to listen. He had heard on two occasions what he divined as a manifest sob, first when the emotional Sadie gave way to tears and again when Helen was aggravated to a petulant outburst of grief. Later when he heard bright laughter and gay exclamations he could hardly believe his ears. He was profoundly troubled and completely bewildered--a dangerous state of mind for a man who has the power of seventy horses under the pressure of his thumb. Nor was his mental turmoil in the least alleviated when, having turned south and being on the point of coasting down a precipitous hill he felt a touch on his shoulder and heard the elder of his two pretty passengers command him in worse French than his own poor English to go slow when he turned into Fifth avenue again and be prepared to stop. Gaston knew that this was in direct violation of his orders from Mrs. Burton, but when he saw a yellow-backed bill flutter down over his shoulder his quick intelligence blazed with understanding. His first groping suspicions had been justified. There was romance in the wind. Steering easily with one hand, Gaston deftly seized the bill and caused it to vanish somewhere in his great fur coat. Sadie Burton had been horror-stricken at this bold proffer of a bribe. Likewise she was alarmed that Helen should put so much trust in Gaston, who seemed to be in mortal terror of her aunt and to quake all through his body when he listened to her commands. As Helen sank back beside her, after letting fall the bribe, the agitated Sadie whispered tremulously: "Are you sure you can trust him, Helen? If he should tell Auntie El she would surely make you a prisoner. You will never get a chance to leave her side at the opera to-night." "Gaston is a Frenchman, my dear," laughed Helen, confidently, "and most Frenchmen--even chauffeurs, I am sure--would cut their hearts out before they would oppose a barrier to the course of true love."