The anthropologist Edward Clodd noted that Crookes had poor eyesight, which may have explained his belief in spiritualist phenomena and quoted William Ramsay as saying that Crookes is "so shortsighted that, despite his unquestioned honesty, he cannot be trusted in what he tells you he has seen." Biographer William Hodson Brock wrote that Crookes was "evidently short-sighted, but did not wear spectacles until the 1890s. Until then he may have used a monocle or pocket magnifying glass when necessary. What limitations this imposed upon his psychic investigations we can only imagine."