The first attempt to slow the lava flow by spraying the leading edge with sea water began on 6 February, and although the volume of water being pumped on was rather small at 100 litres per second (26 US (liquid) gallons per second), the flow was noticeably affected. The lava changed as water poured on it. Before cooling, the flow of the lava was blocky, covered with volcanic bombs and was a reddish oxidised colour. After cooling, the surface became more jagged and was much more difficult to walk on, and the flow surface turned from black to grey. (Richard & James, 1983) Water cooling of the lava was slow but efficient, with almost all the water converted to steam. Once the viability of lava cooling had been proven, efforts to halt the flows were increased.