Optical Connections oF Sir William Crookes

This is well worth a read, the bit about Spiritualism is skipped over but the comments about Anna Eva Fay and Rosina Showers are valid. He tightened his controls in subsequent tests including with Florence Cook. The bit about the close association with the latter is well overstated all because of one book by Trevor Hall using unreliable memoirs from one individual. Wait until Lis's piece becomes public early next year. However you get a very good idea just how influential Crookes was from this.
http://www.opticianonline.net/optical-connnections-work-sir-william-crookes/