I'm looking for a book I remember where aliens came in a very large ship, because they had no air filtration system, to earth seeing the clouds as promise that there could be air. Once they landed in an american city and, tried to kill everyone with their muskets; their ship was studied (because they lost).This book is stuck in my head because the aliens were said to look like stuffed bears and formed up in three rows outside the ship to fire their guns but, I can't remember the title or author of the book.Does anyone know which book I'm talking about?