"pressure" <-
structure(list(temperature = c(0, 20, 40, 60, 80, 100, 120, 140, 160, 180, 
200, 220, 240, 260, 280, 300, 320, 340, 360), pressure = c(0.0002, 0.0012, 
0.006, 0.03, 0.09, 0.27, 0.75, 1.85, 4.2, 8.8, 17.3, 32.1, 57, 96, 157, 
247, 376, 558, 806)), row.names = c("1", "2", "3", "4", "5", "6", "7", 
"8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19"),
class = "data.frame")