Thompson next investigated the insulating properties of various materials, including fur, wool and feathers. He correctly appreciated that the insulating properties of these natural materials arise from the fact that they inhibit the convection of air. He then made the somewhat reckless, and incorrect, inference that air and, in fact, all gases, were perfect non-conductors of heat. He further saw this as evidence of the argument from design, contending that divine providence had arranged for fur on animals in such a way as to guarantee their comfort.