Simplify the following text for a Grade 9 native English-speaking person.
Original: In 1847 Wallace and Bates discussed the idea of an expedition to the Amazon rainforest , the plan being to cover expenses by sending specimens back to London .
Simplified: In 1847 Wallace and Bates discussed the idea of an expedition to the Amazon . The plan was to defray expenses by sending specimens back to London , where an agent would sell them for a commission .