I’ve been working up at the observatory for the past few months and, recently, I was lucky enough to be given a guided tour of this priceless collection of scientific books. Here, then, are a few of the highlights of that tour — chosen by dint of the notability of their punctuation, of course — that take in medieval manuscripts through to Renaissance printed books. I hope you enjoy perusing them as much as I did!
What is perhaps most striking about this page is the material it is made from: look carefully and you will be able to discern a dimpling, or grain, in its surface, a sign that it is made from animal skin parchment. The skin has been scraped so thin that it is almost translucent — this is “vellum”, properly speaking, or fine calfskin parchment — and the writing on the reverse of the leaf is clearly visible. In some cases, in fact, oiled parchment was used for window panes, letting light in even as it kept out the draughts.
In this work, Kepler used ratios derived from the movements of the planets to construct musical scores (as shown here), and proposed his third law of planetary motion, which related the period of a planet’s orbit to its distance from the sun.