The king of Prussia, while he was reviewing his troops in Silesia, in the autumn of the year 1785, caught a severe cold, which settled on his lungs and in the course of nine months brought on symptoms of an approaching dropsy. Zimmerman, by two very flattering letters of the 6th and 16th of June, 1786, was solicited by his majesty to attend him, and he arrived at Potzdam on the 23d of the same month; but he immediately discovered that his royal patient had but little hopes of recovery; and, after trying the effect of such medicines as he thought most likely to afford relief, he returned to Hanover on the 11th of July following.[3] But it was not Frederick alone who discovered his abilities. When in the year 1788, the melancholy state of the king of England’s health alarmed the affection of his subjects, and produced an anxiety throughout Europe for his recovery, the government of Hanover dispatched Zimmerman to Holland, that he might be nearer London, in case his presence there became necessary; and he continued at the Hague until all danger was over. Zimmerman was the first who had the courage to unveil the dangerous principles of the new philosophers, and to exhibit to the eyes of the German princes the risk they ran in neglecting to oppose the progress of so formidable a league. He convinced many of them, and particularly the emperor Leopold II. that the views of these _illuminated_ conspirators were the destruction of Christianity, and the subversion of all regular government. These exertions, while they contributed to lessen the danger which threatened his adopted country, greatly impaired his health.