"USE THE SUN TO TELL TIME"
The sundial seems to have the following letter markings:
6:00 - T 7:00 - S 8:00 - O 9:00 - U 10:00 - M? 11:00 - L 12:00 - R 1:00 - I 2:00 - H 3:00 - P 4:00 - A 5:00 - E 6:00 - C