The strongest evidence to support the thesis is:
"A party of fourteen, including several artists and architects, accompanied Champollion. Deciding to dress like natives, they wore turbans on their heads, gold-embroidered jackets, and yellow boots."
This detail vividly describes the scene and the participants, allowing the reader to visualize the setting and the characters' actions, which effectively supports the idea that Giblin uses description to help readers visualize the events in the book.