The Wonders of Optics

by Fulgence Marion

“After two years’ labour and thought I have succeeded in making an instrument, by the aid of which objects which are too distant to be visible by the eye, are seen plainly. The one I show, although constructed out of bad materials, and simply as an experiment, is, in the judgment of the Stadtholder and of several other persons, as good as the one lately presented to the States-General by a citizen of Middleburg. I am sure of improving it still further in the course of time, and I beg to ask for a patent by which any person who is not already in possession of this invention will be forbidden, under pain of a heavy fine and confiscation, to make or sell similar instruments for twenty-two years.”

The States-General refused to grant the patent in this case also, but enjoined Metius to perfect his instrument, reserving to themselves the power to reward him in the future if they thought fit.

In Italy, Galileo is generally supposed to have discovered independently the method of making a telescope on the principle of the Dutch philosophers, about the beginning of 1609, having received a very imperfect account of these instruments somewhere about that time. It may be remarked that in his letter to the chiefs of the Venetian Republic, giving an account of the properties of these new instruments, Galileo states that, if necessary, they could be made specially for the use of the navy and army belonging to the state. But secrecy was useless, for telescopes were already made and sold in Holland at a cheap rate. Besides, Galileo makes no allusion to the labours of his Dutch predecessors, either in a prior letter handed down to us by Venturi, or in the decree of the Venetian Senate, dated August 5, 1609.

The Italian commentators are in error when they attribute the second discovery of the telescope to the knowledge that Galileo possessed of the laws of refraction, and that it was by deductions therefrom that he was enabled to construct his first instruments.

Huyghens says, in his Treatise on Dioptrics, “I will unhesitatingly place that man above all mortals, who, by the aid of his own reflections and without the aid of accident, first succeeded in constructing a telescope.”

“Let us see,” says Arago, when speaking on this subject, “if Lippershey and John Adrian Metius were men of unparalleled powers.”

Hieronymus Saturnus tells us that an unknown man of genius called upon Lippershey, and ordered from him a number of convex and concave lenses. At the time agreed upon the man returned, and chose two, one convex and the other concave, and, placing them one before his eye and the other at some distance from it, drew them backwards and forwards, without giving any explanation of his manœuvres, paid the optician, and left the place. As soon as he was gone, Lippershey began immediately to imitate the experiments of the stranger, and soon found that distant objects were brought apparently nearer, when the lenses were placed in certain positions. He next fastened them to the ends of a tube, and lost no time in presenting the new instrument to Prince Maurice of Nassau.

According to another version, Lippershey’s children were playing in their father’s shop, and were looking through two lenses, one convex and the other concave, when they found to their surprise that the vane on the clock-tower of Middleburg Church was greatly magnified and apparently brought nearer. The surprise expressed by the children having awakened the attention of Lippershey, he tried the experiment of fixing the lenses on a piece of board; afterwards he tried it again by fixing them at the ends of two pieces of tube, sliding in each other, and succeeded in making the first telescope on record.

The principal documents from which the above facts touching Lippershey have been extracted, are to be found in a memoir on the subject by Olbers, printed in Schumacher’s Astronomical Annual for 1843.

It was said in the time of Galileo that he had in his possession a telescope by the aid of which he could see the birds flying at Fiesole from the window of his palace in Florence. This story does not in the least detract from the merit of the illustrious astronomer, who not only constructed a telescope for himself, but was the first to direct it heavenwards, and that too by purely theoretical researches; for in spite of all the documents adduced above, there is little or no proof that he had ever seen or heard of the Dutchman’s telescope. It is only right, therefore, that the instrument constructed on this principle should be called the Galilean telescope. He afterwards increased its power from four to thirty times, beyond which he could not get with the means at his command. With his imperfect instruments Galileo discovered the satellites of Jupiter, the mountains of the moon, and the spots on the sun, and earned for himself the name of Lynceus, who according to the ancients was one of the Argonauts, possessed of the power of seeing through a wall. Towards the end of his life, when the old man was blind, and the Academy of the Lincei treated his hypotheses with disdain, he would laugh sadly at the name bestowed on him, and the obstinate Academy. [Fig. 41] (see next page) shows the path of the rays in a Galilean telescope. The object-glass O is double convex, and the eye-piece o bi-concave. The image is formed between these lenses, and the eye appears to see it at that point. The States-General complained of being obliged to shut one eye when looking through a telescope, but in 1671 a good Capuchin monk, whose name was Cherubino, placed two telescopes together, little thinking that the moderns would imitate him in that very worldly instrument, the opera-glass.