Quicksilver you can speculate about indgena but until you find some other notable source which puts forward this proposed derivation it should not be included IMO this is highly fanciful if this is to be explained as an english corruption of a spanish word how do you then account for the very many references in spanish documents of the time to los Indios the people and las Indias the place Surely native spanish speakers themselves would not get confused between indgena and references to the East Indies las Indias Orientales Whether Columbus really believed what he wrote about reaching the Indies we can only speculate Eratostheness relatively accurate calculation of the Earths circumference was only one estimate amongst many was not generally held and AFAIK weve nothing to indicate that Columbus accepted or relied on this figure     September  UTC