In the passage "Cooling the Lava," what are past human attempts to control lava flows?

In the nonfiction book, The Control of Nature, McPhee states that humans have attempted to "cool the lava" in a variety of ways. McPhee first talks about spraying water on the lava in an attempt to solidify the molten hot lava. The second attempt involved making an animal sacrafice to the volcano god, Hephaestus. The last method that McPhee mentions is the attempt to cool the lava by dumping icey water out of a helicopter, in addition to using "cold fans". This fonal attempt actually succeeded in making a slight impact on the lava flow.