In July 1852 , while returning to the UK , the ship 's cargo caught fire and all the specimens he had collected were lost .
Wallace charted the Rio Negro for four years , collecting specimens and making notes on peoples , geography , flora , and fauna .
In July 1852 , while returning to the UK , the ship 's cargo caught fire and all the specimens Wallace had collected were lost .
Wallace charted the Rio Negro for four years , collecting specimens and making notes on peoples , geography , flora , and fauna .