Galileo made no secret of his invention. It was called "Galileo's Tube," but some of the priests called it Galileo's "Magic Tube."
Yet it marked an era in the scientific world. Galileo endeavored constantly to improve his instrument; and from a threefold magnifying power, he finally made one that magnified thirty-two times.
Galileo made hundreds of telescopes, and sold them at moderate prices to any one who would buy. He explained minutely the construction of the instrument, showing clearly how it was made in accordance with the natural laws of optics. His desire was to dissipate the superstition that there was something diabolical or supernatural about the "Magic Tube"--that, in fact, it was not magic, and the operator had no peculiar powers; you had simply to comply with the laws of Nature, and any one could see for himself.
It is hard for us, at this day, to understand the opposition that sprang up against the telescope. We must remember that at this time belief in witchcraft, fairies, sprites, ghosts, hobgoblins, magic and supernatural powers was common. Men who believe in miracles make rather poor scientists.
There were books about "Magic," written by so-called scientific men, whose standing in the world was quite as high as that of Galileo.
In Sixteen Hundred Ten, Galileo published his book entitled, "Sidera Medicea," wherein he described the wonders that could be seen in the heavens by the aid of the telescope. Among other things, he said the Milky Way was not a great streak of light, but was composed of a multitude of stars; and he made a map of the stars that could be seen only with the aid of the telescope.
There resided in Venice at this time a scientific man by the name of Porta, who was much more popular than Galileo. He was a priest, whose piety and learning was unimpeached.
The year after Galileo issued his book, Porta put out a work much more pretentious, called "Natural Magic." In this book Porta does not claim that magicians all have supernatural powers; but he goes on to prove how they deceive the world by the use of their peculiar apparatus, and intimates that they sometimes sell their souls to the Devil, and then are positively dangerous. He dives deep into science, history and his own imagination to prove things.