The difference between the two types of smart cards is the manner with which the microprocessor on the card communicates with the outside world. A contact smart card has eight contact points, which must physically touch the contacts on the reader to convey information between them. Since contact cards must be inserted into readers carefully in the proper orientation, the speed and convenience of such a transaction is not acceptable for most access control applications. The use of contact smart cards as physical access control is limited mostly to parking applications when payment data is stored in card memory, and when the speed of transactions is not as important.

In the late 1920s and early 1930s there were around one quarter of a million practising Spiritualists and some two thousand Spiritualist societies in the UK in addition to flourishing microcultures of platform mediumship and 'home circles'.[18] Spiritualism continues to be practiced, primarily through various denominational spiritualist churches in the United States, Canada, Australia and the United Kingdom. In the United Kingdom, over 340 spiritualist churches and centres open their doors to the public and free demonstrations of mediumship are regularly performed.[19]
Some scientists of the period who investigated spiritualism also became converts. They included chemist Robert Hare, physicist William Crookes (1832–1919) and evolutionary biologist Alfred Russel Wallace (1823–1913).[13][14] Nobel laureate Pierre Curie took a very serious scientific interest in the work of medium Eusapia Palladino.[15] Other prominent adherents included journalist and pacifist William T. Stead (1849–1912)[16] and physician and author Arthur Conan Doyle (1859–1930).[17]