A Japanese paper balloon landed in a tree near the Charles Lafffranchini Ranch 2½ miles northwest of here on the afternoon of February 1, 1945, and later exploded, leaving the gas valve lines, ballast, four bombs, sandbags, and the bomb carriage unit. Made of paper and glue, it had been launched into the jet stream by the Japanese Army. Such balloon incidents were among the best kept secrets of World War II.