 Numerous other philosophers and scientists, including Isaac Newton (1704), Erasmus Darwin (1790) and Wilhelm Wundt (1874) may have referred to synesthesia, or at least synesthesia-like mappings between colors and musical notes.Henry David Thoreau remarked in a letter to Ralph Waldo Emerson in 1848 that a child he knew had asked him "if I did not use ‘"colored" words.’ She said that she could tell the color of a great many words, and amused the children at school by so doing.