Pliny's last work, according to his nephew, was the "Naturalis Historia" ("Natural History"), an encyclopedia into which he collected much of the knowledge of his time. It comprised 37 books. His sources were personal experience, his own prior works (such as the work on Germania), and extracts from other works. These extracts were collected in the following manner: One servant would read aloud, and another would write the extract as dictated by Pliny. He is said to have dictated extracts while taking a bath. In winter, he furnished the copier with gloves and long sleeves so his writing hand would not stiffen with cold (Pliny the Younger in "avunculus meus"). His extract collection finally reached about 160 volumes, which Larcius Licinius, the Praetorian legate of Hispania Tarraconensis, unsuccessfully offered to purchase for 400,000 "sesterces." That would have been in 73/74 (see above). Pliny bequeathed the extracts to his nephew.