Please add spaces between words: HewasappointedtoachairatBerlinAcademyattheageofonly19.FrederickIIaskedhimtorevivetheastronomicalobservatoryoftheAcademybutthiswasnotataskforwhichJohann(III)wasparticularlywellsuited.
He was appointed to a chair at Berlin Academy at the age of only 19. Frederick II asked him to revive the astronomical observatory of the Academy but this was not a task for which Johann(III) was particularly well suited.