This was in the closing days of the French monarchy, and the ascent of the Montgolfiers' first hot-air balloon in 1783 which shall be told more fully in its place put an end to all French experiments with heavier-than-air apparatus, though in England the genius of Cayley was about to bud, and even in France there were those who understood that ballooning was not true flight.
For practical purposes, it will suffice if the method of heating and ventilating a bath on the hot-air principle be explained. This I shall now do, and subsequently give plans and instructions for methods of heating and ventilating on systems where, by the exposure of the heating surfaces of furnaces, a large proportion of radiant heat is thrown into the hot-rooms.
This cooling is rendered necessary, because without it the oil would be carbonized, and lubrication of the cylinder rendered impossible. Indeed, a similar difficulty has occurred with all hot-air engines, and is, I think, the reason they have not been more generally adopted.
The Gusher should have been in the Diplomatic Service. One of his hot Specialties was to get up at Dinner Parties and propose Toasts. He would hot-air the Ladies until they flushed Crimson from the Joy of being hot-aired. Even if the Speech was known to be cut-and-dried Blarney, it never failed to swell the Adorable Creatures, as he called them.
The nights were still cold, and when they reached the Rue de l'Annonciation, where the church of Notre-Dame-de-Grace stands, the child was shivering all over. "The church is heated," said her mother. "We must secure a place near a hot-air pipe."
He went into the over-ornate bedroom in which Nita Leigh Selim had been murdered shot through the back as she sat at her dressing-table powdering her face. If her murder had been accomplished by mechanical means, how had it been done? There was no hot-air register here....
She tried to persuade her father to use a hot-air plough, and to give up the practice of keeping cows in an age when milk and butter were considered not only unnecessary, but injurious to human health.
"Then you're about fifteen miles away," commented Mr. Swift. "You can hardly get back before night. Must you go there?" "Left my clothes there. Also a valuable gas balloon. No more hot-air ones for me. Guess I'd better go back," and the aeronaut continued to speak in his quick, jerky sentences. "We'd be very glad to have you come with us, Mr. Sharp," went on the inventor.
At this moment the open hot-air register began to speak, carrying up the voices from the rooms below. As the subject under discussion was the closest to the boys' hearts for the moment, they drew near to listen. "It's Mr. Kincaid himself!" breathed Bobby. "I've been trying to catch you all the way up the street," Mr. Kincaid was saying, "but you walk like a steam engine."
He slipped through the claws of the demons and fell headlong on the Forum at Rome, breaking his neck. The 'demons' may have been some primitive form of hot-air balloon, or a glider with which the magician attempted to rise into the wind; more probably, however, Simon threatened to ascend and made the attempt with apparatus as unsuitable as Bladud's wings, paying the inevitable penalty.