Kircher's first work on magnetism, Ars Magnesia, had contained only modest woodcut illustrations. In contrast Magnes was illustrated not only with more than 150 woodcuts but with 32 full-page engraved plates. It was the first of Kircher's works to combine woodcuts with copperplate engravings. These illustrations were both technically challenging to create and expensive to produce. Two of the illustrations were of machines with moving parts, and readers could cut the parts out and use to create working models of the machinery themselves. On reading the first edition soon after it was published, Evangelista Torricelli wrote to his teacher Galileo that it was a pleasure to read and "enriched with a wealth of beautiful engravings."