claims of duty and business; for to admire art we need leisure and profound stillness (XXXVI:27). Mining Pliny provides lucid descriptions of Roman mining. He describes gold mining in detail, with large-scale use of water to scour alluvial gold deposits. The description probably refers to mining in Northern Spain, especially at the large Las Médulas site. Pliny describes methods of underground mining, including the use of fire-setting to attack the gold-bearing rock and so extract the ore. In another part of his work, Pliny describes the use of undermining to gain access to the veins. Pliny was scathing about the search for precious metals and gemstones: "Gangadia or quartzite is considered the hardest of all things – except for the greed for gold, which is even more stubborn." Book XXXIV covers the base metals, their uses and their extraction. Copper mining is mentioned, using a variety of ores including copper pyrites and marcasite, some of the mining being underground, some on the surface. Iron mining is covered, followed by lead and tin. Reception Medieval and early modern The anonymous fourth-century compilation Medicina Plinii contains more than 1,100 pharmacological recipes, the vast majority of them from the Historia naturalis; perhaps because Pliny's name was attached to it, it enjoyed huge popularity in the Middle Ages. Isidore of Seville's Etymologiae (The Etymologies, c. 600–625) quotes from Pliny 45 times in Book XII alone; Books XII, XIII and XIV are all based largely on the Natural History. Through Isidore, Vincent of Beauvais's Speculum Maius (The Great Mirror, c. 1235–1264) also used Pliny as a source for his own work. In this regard, Pliny's influence over the medieval period has been argued to be quite extensive. For example, one twentieth century historian has argued that Pliny's reliance on book-based knowledge, and not direct observation, shaped intellectual life to the degree that it "stymie[d] the progress of western science". This sentiment can be observed in the early modern period when Niccolò Leoniceno's 1509 De Erroribus Plinii ("On Pliny's Errors") attacked Pliny for lacking a proper scientific method, unlike Theophrastus or Dioscorides, and for lacking knowledge of philosophy or medicine. Sir Thomas Browne expressed scepticism about Pliny's dependability in his 1646 Pseudodoxia Epidemica: Modern Grundy Steiner of Northwestern University, in a 1955 judgement considered by Thomas R. Laehn to represent the collective opinion of Pliny's critics, wrote of Pliny that "He was not an original, creative