According to the 1946 book "Hiroshima" and other books which cover both bombings, in the days between the atomic bombings of Hiroshima and Nagasaki, some survivors of the first bombing went to Nagasaki and taught others about ducking after the atomic "flash" and informed them about the particularly dangerous threat of imploding window glass. As a result of this and other factors, far fewer died in the initial blast at Nagasaki as compared to those who were not taught to duck and cover. The general population however was not warned of the heat or blast danger following an atomic flash, due to the new and unknown nature of the atomic bomb. Many people in Hiroshima and Nagasaki died while searching the skies, curious to locate the source of the brilliant flash.