ABSTRACT
Euler later developed a series similar to that of Bernoulli, which was also a Bessel
function, and Bessel's equation appeared in a 1764 article by Euler dealing with the
vibrations of a circular drumhead. J. Fourier (1768-1836) also used Bessel functions in
his classical treatise on heat in 1822, but it was Bessel who first recognized their special
properties.
