Inigo Jones carried the information and experience thus obtained with him on this his second visit to Italy. He enquired why such a building had such an effect. He made careful measurements, and compared and combined the figures so arrived at until he wrung the secret of the old Roman builder from the ruins. Cunningham dwells at some length on this subject. There can be no doubt that, like Wren’s, the genius of Jones consisted mainly in his extraordinary power of taking pains. Where one man was content to observe the completeness and harmony of some palace or church, Jones must find out to what cause that harmony was due. Thus he went about making measurements. For instance, he always carried a copy of the great work of Andrea Palladio with him wherever he went. On the fly-leaves he constantly wrote such notes as this:—“The length of the great courte at Windsour is 350ᶠᵒ, the breadth is 260; this I measured by paces the 5 of December, 1690. The great court at Theobalds is 159ᶠᵒ, the second court is 110ᶠᵒ square, the thirde courte is 88ᶠᵒ—the 20 of June, 1621.” The book is now at Worcester College, Oxford. One of his notes is very curious as showing his subtle analysis of proportion. He had a great admiration for the Temple of Jupiter at Rome, and set seriously to work to find out the reason for its satisfactory effect. In the result he came to the conclusion that its design was based on a series of circles, and that its proportions were fixed by dividing the largest diameter into six parts, and then recombining them. In June, 1639, he noted of this temple that it had just been destroyed by the Pope’s permission for the sake of the marble built into the walls. The Bishops of London have here ancient precedent for their treatment of Wren’s City churches, and what Inigo would have thought of some recent doings may be gathered from the next two notes:—“This was the noblest thing which was in Rome in my time. So as all the good of the ancients will be ruined ere long.”