In his book, published in 1892, Grey used the same metaphor that Jordan used in her book, which was published in 1885. The metaphor is so unusual that there is little chance that two different people independently created it. Ttherefore, it is highly likely that Grey read Jordan' s book.
The statement 'Jordan used the same metaphor in a work that she wrote in 1894 and published in 1895' most weakens the argument.