It is a curve described by the polar equation: r= 1+2sin(φ/2), (note the 2 in front of sine) named after and English mathematician T. J. Freeth (1819-1904) which first appeared in a paper he published in the London Mathematical Society in 1879.
It is considered an extention of Freeths strophoid which is generalized by the equation:
r= a[1+bsin(φ/2)]
See also information at: http://mathworld.wolfram.com/FreethsNephroid.HTML
A nephroid has 2 lines of symmetry.
Evelyn Freeth was born in 1846.
Evelyn Freeth died in 1911.
Ben Freeth was born in 1971.
George Freeth was born in 1883.
George Freeth died in 1919.
Rodger Freeth died in 1993.
Rodger Freeth was born in 1950.
James Freeth was born in 1786.
Denzil Freeth died in 2010.
Denzil Freeth was born in 1924.
Andrew Freeth died in 1986.