Excerpt from Blood Work: A Tale of Medicine and Murder in the Scientific Revolution by Holly Tucker:

Huygens speculated instead that something was fluttering around Saturn. “The ears of Saturn,” he wrote in 1658 in an encrypted letter intended for the Montmor Academy, “can be nothing other than what I put forth in my anagram”: 

a  c  d  e  g  h  i  l  m  n  o  p q  r  s  t  u 

6 5 1 5 1 1 7 4 2 9 4 2 1 2 1 5 5 

The numbers indicated how many times each letter appeared in the enigma, which when rearranged formed the words Annulo cingitur tenui, plano, nusquam cohaerente ad eclipticam inclinato: “Saturn is encircled by a thin, flat ring, nowhere touching, inclined to the ecliptic.”