A 15-year-old Cook, alone in Crookes' house with Crookes' friends and family as witnesses, was said to have materialized the spirit of Katie King, who walked about, talked, allowed herself to be weighed and measured, and even held the family's baby (Doyle 1926: volume 1, 241). On one occasion, at a joint seance in Crookes' home in March 1874, Katie King was seen in company with "Florence Maple", a spirit materialised by the medium Mary Showers who was exposed as a fraud shortly thereafter. The sessions were held with the medium secluded in the dark, because Spiritualists believe that materialization requires very dim surroundings to succeed, though occasionally the spirits materialised in the light and some photographs were taken. As is apparently typical of materialized spirits, Katie's exact height and weight varied, though Katie was always taller than Florence Cook, with a larger face, and different hair and skin. According to those present, the two were both visible at the same moments, so that Florence could not have assumed the role of the spirit (Doyle 1926: volume 1, 235-240).