Use your brains, the arrow turning into rain and fire could be the description by a person with no science knowledge of a firecracker or gun. Science was highly developed thousands of years ago, highly knowledgeable persons inhabited Bharath and these have died out and their stories with them. What has been handed down by word of mouth is obviously distorted through the centuries and if you accept what is written literally is appears foolish, but if you apply a little brains to the issue, you will see a remarkable similarity with the so called hitech inventions that today's scientists are in the process of "inventing".
