“And an atlas,” Simon called after him. Alex broke into a jog.

He took enough time in the house to check on the boys and to bring out sweaters and jackets, but he returned in time to hear Lucy ask his father an interesting question.

“What of Dido, Henry? What was she pleased to see?”

“When Queen Dido was jilted by Aeneas and threw herself on a funeral pyre, Juno took pity on her and sent Iris on a rainbow to release Dido’s soul, by cutting a lock of her hair. It was the rainbow she was happy to see. The idea of a person’s soul leaving their body as long as it had an object to cleave to was common in classicism; and the rainbow was the bridge to high wisdom, and the initiation into paradise.”

“Newton was musing on an iconic symbol.” Alex’s eyes engaged with Lucy’s as he helped her into an oversized cardigan. They had been introduced to this symbol of higher wisdom together; and he started to wonder whether anyone’s soul was residing in the object she’d retrieved from under the tree.

Everyone was absorbed in their own thoughts and research for some time, when Lucy, who had been busying herself in the Shakespeare volume, looked up excitedly. “Lines from his thirty-fourth sonnet—the closing couplet—are in several of the texts. ‘Ah! But those tears are pearl which thy love sheeds.’” She spoke to a circle of concentrated faces.

Simon had also struck gold in the atlas, scouring the meridians of longitude and latitude at thirty-four degrees. Something clicked for him, and he talked them through his awareness that the Ancient Mariner, sailing south “towards the Line,” had made Lucy and him first think of Sydney, on their plane trip. “Sure enough, Botany Bay is a later name for Stingray Bay, and it’s situated at thirty-four degrees south latitude. Lucy’s birthplace.” He looked up and grinned: “And I’ve just understood your mother, Alex. ‘Following in Eve’s footsteps’ is surely a reference to the fossilized prints found near Cape Town, of the oldest known ancestress of Homo sapiens—‘Eve.’ The whole line, from Cape Town to Port Elizabeth, is an archaeological treasure trove regarded as the cradle of man. At thirty-four degrees south latitude, naturally.”

Lucy, like the others, was hardly surprised anymore. But it brought up a problem, which she now voiced. “Does it suggest a place other than England, do you think, which might house the so-called pot of gold? Could Dee have placed this—whatever it is—on one of his travels abroad?”