Complex sentence: The board met several times at Badajoz and Elvas, without reaching an agreement: the geographic knowledge at that time was inadequate for an accurate assignment of longitude, and each group simply chose maps or globes that showed the islands in their own hemisphere.
Split into simpler sentences: The board met several times at Badajoz and Elvas, without reaching an agreement. Geographic knowledge at that time was inadequate for an accurate assignment of longitude, and each group simply chose maps or globes that showed the islands in their own hemisphere.