ogy, putting down his theoretical and practical knowledge of metals and mining. Not only this, but the new work was also to contain his reflections on the origin of matter. That part of it was to be a philosophizing scientist's view of the world.
By 1731 Swedenborg had practically finished this work, and by 1733 he was given leave of absence from the Board of Mines in order to finish his researches for the mining matters in the book and also to have it published abroad.12
He kept a diary '3 for most of this journey through Dresden to Prague, recording what he saw with such meticulousness that it must have been intended as a report to the Board. It was mostly about mining processes and metallurgy, but it also had his observations on the making of arsenic, cobalt blue, mirrors, peat-fuel, saltboiling, in fact on any method of manufacturing, anything into which he could steal a look. He proved himself an acute factual observer. Having seen a thing once he seemed able to report every technical detail.
To scenery he gave vague appreciative tributes now and then, but gardens interested him passionately, especially those with orange and lemon trees, whose very measurements he took. He noted buildings and the general condition of people, but he was even more on the lookout for books. He found one on the kinds of worms that destroy ships and wooden piles as well as remedies against them. Into his diary went a résumé, with his own observations attached. In every library of consequence be searched for scientific books, recording his disappointment when he found mainly "old codexes." The makers of books he sought as well. "It would be too prolix to mention all the learned men I visited and with whom I became acquainted on these journeys, since I never missed an opportunity of doing so. . . ."
In July, 1734, Swedenborg was home again, with the prestige of a solid and successful book behind him. While he was in Leipzig, he had seen through the press, at the expense and with the admiration of his intelligent friend and patron, Duke Rudolph of Brunswick, the three big volumes of his Opera Philosophica et Mineralia ("Philosophic and Mineralogical Works").
The first volume, Principia Rerum Naturalium ("The First
