We are reminded of the association between architecture and military engineering during the height of the Italian Renaissance, by “To build in the Sea, Forts, Moles, etc.” and “Secure and Speedier Ways of attacking Forts than by Approaches and Galleries.” Sanmicheli had invented the pentagonal bastion: Inigo Jones had fortified Basing House against the Parliament’s attack, and had been one of the defenders. We would give much to learn something of Wren’s invention for “Ways of Submarine Navigation.” If he had developed “Easier Ways of Whale-fishing,” it would have given material for another chapter in _Moby Dick_. _Eheu fugaces!_ There is a hint of the coming gramophone in “A speaking Organ, articulating Sounds,” and “Divers new Musical Instruments” helps to explain Wren’s devotion to his daughter Jane, whose monument in the crypt of St. Paul’s--she died at the age of twenty-six--shows her in Francis Bird’s rather heavy-handed sculpture as seated at an organ. The technique of writing always interested Wren, so it is natural to find in the catalogue “To write in the Dark” and “To write Double by an Instrument,” the latter a dodge he developed to the point of patenting it. The tools of his future profession already attracted him. “A Scenographical Instrument, to survey at one Station” is followed by “A Perspective Box, to survey with it,” and there is a ring of Bacon and Wotton in the compendious phrase “New Designs tending to Strength, Convenience, and Beauty in Building.” There is certainly no more rightly prophetic entry in the whole astonishing list. “Several new Ways of graving and etching” gives a certain colour to the story--though it must be discredited--that Wren introduced mezzotint. “New Ways of Intelligence, new Cyphers” marks his early attachment to an amusement which he shared with others of his day, though without the need to use the art to conceal roguish passages in what he wrote, as was the case with Pepys’ shorthand. His later excursions into veterinary surgery and the transfusion of human blood are heralded by the memorandum “To purge or vomit, or alter the Mass by Injection into the Blood, by Plaisters, by various dressing a Fontanell.” We have a glimpse of the experiments connected with the working out of “A Pavement harder, fairer, and cheaper than Marble,” as well as into the social side of these Wadham assemblies, through John Evelyn’s glasses. On July 13, 1654, he was at Dr. Wilkins’, at Wadham, and saw: “Variety of shadows, dyals, perspectives, and many other mathematical and magical curiosities, a way-wiser, a thermometer, a monstrous magnet, conic and other sections, a ballance on a demi-circle, most of them of his own and that prodigious young scholar Mr. Chr. Wren, who presented me with a piece of white marble, which he had stain’d with a lively red, very deepe, as beautiful as if it had been natural.”