of the chief philosophical instrument-maker of Bologna. He took great pleasure in showing me the various instruments he manufactured; but still there was a certain air f presumption about him, which seemed to indicate a less amount of knowledge than I should otherwise have assigned to him. I had on the preceding day mentioned to my Italian friend, who now accompanied me, that there existed a very simple method of punching a hole in a piece of glass, which, as he was much interested about it, I promised to show him on the earliest opportunity.
Finding myself in the workshop of the first instrument maker in Bologna, and observing the few tools I wanted, I thought it a good opportunity to explain the process to my friend; but I could only do this by applying to the master for the loan of some tools. I also thought it possible that the method was known to him, and that, having more practice, he would do the work better than myself.
I therefore mentioned the circumstance of my promise, and asked the master whether he was acquainted with the process. His reply was, "Yes; we do it every day." I then handed over to him the punch and the piece of glass, declaring that a mere amateur, who only occasionally practised it could not venture to operate before the first instrument-maker in Bologna, and in his own workshop.
I had observed a certain shade of surprise glance across the face of one of the workmen who heard the assertion of this daily practice of his master's, and, as I had my doubts of it, I contrived to put him in such a position that he must either retract his statement or else attempt to do the trick.
He then called for a flat piece of iron with a small hole in it. Placing the piece of glass upon the top of this bit of iron, and holding the punch upon it directly above the aper-
