A new generation of professors arose in Halle. C. B. Michaelis, the younger Francke, Freilinghausen, the elder Knapp, Callenberg, and Baumgarten, took the place of their more vigorous predecessors. It is deplorable to see how Pietism now began to lose its first power and earnest spirit. The persistent inquiry into scriptural truth passed over into a tacit acquiescence of the understanding. Reliance was placed on the convictions, more than on the fruits of study. Spener had blended the emotions of the mind and heart, reason and faith, harmoniously; but the later Pietists cast off the former and blindly followed the latter. Hence they soon found themselves indulging in superstition, and repeating many of the errors of some of the most deluded Mystics. Science was frowned upon, because of its supposed conflict with the letter of Scripture. The language of Spener and Francke, which was full of practical earnestness, came into disuse. Definitions became loose and vague. The _Collegia_, which had done so much good, now grew formal, cold, and disputatious. The missions, which had begun very auspiciously, dwindled from want of means and men. External life became pharisaical. Great weight was attached to long prayers. A Duke of Coburg required the masters of schools to utter a long prayer in his presence, as a test of fitness for advancement. Pietism grew mystical, ascetic, and superstitious. Some of its advocates and votaries made great pretensions to holiness and unusual gifts. This had a tendency to bring the system into disrepute in certain quarters, though the good influences that it had exerted still existed and increased. It might disappear, but the good achieved by it would live after it. But a strong effort was made by Frederic William I. to maintain its prominence and weight. From 1729 to 1736, he continued his edict that no Lutheran theologian should be appointed in a Prussian pulpit who had not studied at least two years in Halle, and received from the faculty a testimonial of his state of grace. But when he was succeeded by Frederic II., commonly called Frederic the Great, that University no longer enjoyed the royal patronage, and Halle, instead of being the school of practical piety and scriptural study, degenerated into a seminary of Rationalism.