Second Sight, or Two Person Mental Act is an act of two partners who seemingly are able to know one another's thoughts. Typically, one of the partners is Blindfolded while the other one goes out into the audience getting items for the blindfolded partner to identify. The item is either handed to the person or something is whispered.
This is often referred to as clairvoyance or telepathy by psychics.
A method was reported in Reginald Scot in his classic treatise, The Discoverie of Witchcraft and was performed in 1831 by the "Double-sighted Phenomenon," an eight-year-old Scottish boy named Louis Gordon M'Kean. While blindfolded and facing away from the audience, he could identify objects and repeat what others had spoken with a whispered at a distance of a hundred yards.
The first use of the term "second sight" was by John Henry Anderson around 1838 for his magic act that featured his blindfolded daughter that he billed as "the Second-Sighted Sybil." Anderson would go into the audience to get objects for his daughter to reveal.
English female magician Georgiana Elizabeth Eagle performed her second sight act as "The Mysterious Lady" and "Gilliland Card" from 1841 to 1886.
Robert-Houdin's was also doing a second sight act with his son around 1846 in Paris.
Notable Teams that presented Second Sight Acts
- Albany (1886)
- The Steens
- The Lorenz Svengali Trio - used music from 1900 to 1925, playing the United States and Europe.
- The Zomahs
- Houdini and Bess
- The Trees
- Lucille and Eddie Roberts
- Robert Heller & wife, Miss Hadee Heller 
- Mercedes and Mlle. Stantone (vaudeville) - she played any tune whispered to her partner.
- Liz and Tom Tucker
- Julius & Agnes Zancig
- The Piddingtons
- Arthur Buckley and his wife Helen.
- Simon Aronson & wife, Ginny
- Odronoff (1889-1975) & wife Lizz. Real name Juan Manuel Zolezzi.
- 13 Steps to Mentalism by Corinda - Chapter VIII (1959-1960)
- Self-working Mental Magic By Karl Fulves (1979)
- Len Belcher on Two-Person Mentalism by Len Belcher (1974)
- The Secret Life of Houdini By William Kalush, page 138 (2006)