The Latin inscription reads
Omnem crede diem tibi diluxisse supremum,
grata superveniet quae non sperabitur hora. This inscription is taken from Horace,
Epistles, circa 20 BC Book 1 Epistle IV, lines 15-16 and translates to "Believe that each day that shines on you is your last, the hour to which you do not look forward will come as a welcome surprise."
A sundial with Jewish hours, 1697, was in the Michael and Judy Steinhardt Judaica Collection, Sotheby's New York, 29 April 2011, lot 60. Jewish hours are calculated by dividing the total hours of daylight and nighttime into twelve equal parts, thus vary by season and even by each day.