Common minke whale produce downswept calls of 250 to 50 Hz. The first written records attest to the active hunting of minke whales off Norway by 1100 A.D. By 1240 they began utilizing iron darts fired from crossbows that had been treated with the tissue of dead sheep infected with the bacterium "Clostridium". Introducing this infectious agent to a wound weakened the whale and after a couple days the men would return and lance it to death. This method of whaling continued to be used until the 1880s. Norwegian catching of minke whales from small fishing vessels started off Møre, western Norway, in
What is a Masterpiece? confluence of memories and emotions forming a single idea", that it has "a power of recreating traditional forms so that they become expressive of an artist's own epoch and yet keep a relationship to the past". The highest masterpieces are said to be "illustrations of great themes." Clark also implicitly excluded the erotic from considerations of what constituted a masterpiece, based on his perspective that a necessary condition is the balance between sense and form (works that are too sensual are, therefore, unbalanced and not to be categorised at masterpiece level). What is a Masterpiece? What is a Masterpiece? is