"A hundred and forty degrees, centigrade, below zero!" [Illustration: IT'S COLD ENOUGH TO FREEZE A WHITE BEAR.] "Two hundred and twenty degrees, Fahrenheit, below zero!" cried M'Nicholl; "no wonder that we should feel a little chilly!" "Pouillet is right, then," said Barbican, "and Fourier wrong." "Another victory for Sorbonne over the Academy!" cried Ardan. "_Vive la Sorbonne!_ Not that I'm a bit proud of finding myself in the midst of a temperature so very _distingue_--though it is more than three times colder than Hayes ever felt it at Humboldt Glacier or Nevenoff at Yakoutsk. If Madame the Moon becomes as cold as this every time that her surface is withdrawn from the sunlight for fourteen days, I don't think, boys, that her hospitality is much to hanker after!" CHAPTER XV. GLIMPSES AT THE INVISIBLE. In spite of the dreadful condition in which the three friends now found themselves, and the still more dreadful future that awaited them, it must be acknowledged that Ardan bravely kept up his spirits. And his companions were just as cheerful. Their philosophy was quite simple and perfectly intelligible. What they could bear, they bore without murmuring. When it became unbearable, they only complained, if complaining would do any good. Imprisoned in an iron shroud, flying through profound darkness into the infinite abysses of space, nearly a quarter million of miles distant from all human aid, freezing with the icy cold, their little stock not only of gas but of _air_ rapidly running lower and lower, a near future of the most impenetrable obscurity looming up before them, they never once thought of wasting time in asking such useless questions as where they were going, or what fate was about to befall them. Knowing that no good could possibly result from inaction or despair, they carefully kept their wits about them, making their experiments and recording their observations as calmly and as deliberately as if they were working at home in the quiet retirement of their own cabinets. Any other course of action, however, would have been perfectly absurd on their part, and this no one knew better than themselves. Even if desirous to act otherwise, what could they have done? As powerless over the Projectile as a baby over a locomotive, they could neither clap brakes to its movement nor switch off its direction. A sailor can turn his ship's head at pleasure; an aeronaut has little trouble, by means of his ballast and his throttle-valve, in giving a vertical movement to his balloon. But nothing of this kind could our travellers attempt. No helm, or ballast, or throttle-valve could avail them now. Nothing in the world could be done to prevent things from following their own course to the bitter end.