In his book on Microscopy, entitled _Micrographia_, Hooke gives a quaint account of the making of a microscope. “Could we make a microscope,” he writes, “to have only one refraction, it would _cæteris paribus_, far excel any other that had a greater number. And hence it is, that if you take a very clear piece of a broken Venice glass, and in a Lamp draw it out into very small hairs or threads, then holding the ends of these threads in the flame, till they melt and run into a small round Globul, or drop, which will hang at the end of the thread; and if further you stick several of these upon the end of a stick with a little sealing wax, so that the threads stand upwards, and then on a whetstone first grind off a good part of them, and afterward on a smooth Metal plate, with a little Tripoly, rub them till they come to be very smooth; if one of these be fixt with a little soft wax against a small needle hole, prick’d through a thin Plate of Brass, Lead, Pewter, or any other Metal, and an Object, plac’d very near, be look’d at through it, it will both magnifie and make some Objects more distinct than any of the great Microscopes.” This early worker was noted for the variety of his investigations rather than for the depths of his learning. Amongst the so-called Observations, in his book are many that are not connected with microscopic work. The following are interesting and, in the curious old book _Micrographia_, there are an extraordinary number of well executed illustrations. Early in his book Hooke compares various man-made objects, such as a razor edge, the point of a needle and a piece of cloth, with various natural objects, and always to the detriment of the former. He examined _Foraminifera_ with his microscope, and was probably the first man to draw these beautiful little creatures. Petrified wood and charcoal also came under his notice. When he studied cork, he observed that it was made up of “little boxes or cells,” and the name cell has survived to this day despite the fact that it is by no means an appropriate term. That Hooke’s knowledge was not very deep is shown by the fact that he presumed cork to be a fungus growing on the bark of trees.