"Doubtless," said Mr. Knox, "we think it would not be possible for things to happen as they are narrated, but I am not quite sure about that. One of the stories, for instance, tells how a man went through the air on a carpet. We think it cannot be true, but here is a pamphlet which tells how Henry Cavendish, in England, a little while ago discovered a gas which he calls hydrogen. It is ten times lighter than air--so light that another gentleman, Mr. Black, filled a bag with it which took him off his feet and carried him round the room, to the astonishment of all who beheld it. I shouldn't be surprised if by and by we shall be able to travel through the air by a bag filled with such gas." Robert listened with intense interest, not being able to comprehend how anything could be lighter than air. He was not quite sure that his father and mother would approve of his reading a book that was not strictly true, and he was sure that the good minister and deacons of the church would shake their heads solemnly were they to know it; but he could read it on his way home and hide it in the haymow and read it on rainy days in the barn. But that would not be manly. No, he could not do that. He would tell his father and mother and Rachel about it, and read it to them by the kitchen fire. Hit or miss, he would purchase the book. Mr. Knox kindly offered to show him the Town House. They crossed the street, and entered the council chamber. Lieutenant-Governor Hutchinson and the members of the council were sitting in their armchairs, wearing white wigs and scarlet cloaks. Their gold-laced hats were lying on their desks. Lieutenant-Colonel Dalrymple, commanding the king's troops, was seated by the side of Governor Hutchinson as a visitor. Upon the walls were portraits of Kings Charles II. and James II. in gilded frames; also portraits of Governors Winthrop, Endicott, and Bradstreet. Thanking Mr. Knox for his kindness, Robert passed into the street, took a look at the stocks and pillory, and wondered if that was the best way to punish those who had committed petty offenses.