  Annotated parallel text in Latin and English of the classic paper of Adam
Adamandy Kocha\'nski "Observationes Cyclometricae", published in Acta
Eruditorum 4:394--398 (1685), in which he presented approximate geometric
method of rectification of the circle, as well as a series of rational
approximations of \pi. The included Latin text of Observationes closely follows
the original text published in Acta Eruditorum. Punctuation, capitalization,
and mathematical notation have been preserved. Several misprints which appeared
in the original are also reproduced unchanged, but with a footnote indicating
correction. Every effort has been made to preserve the layout of original
tables. The translation is as faithful as possible, often literal, and it is
mainly intended to be of help to those who wish to study the original Latin
text.
