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