Mercedes of Castile; Or, the Voyage to Cathay. by J. Fenimore Cooper.

Although the manner in which these words were uttered lent them weight, the prelate fancied that the mind of the navigator had got to be unsettled by his long contemplation of a single subject. The only things that left any doubt concerning the accuracy of this opinion, were the method and science with which he had often maintained, even in his own presence, the reasonableness of his geographical suppositions; arguments which, though they had failed to convince one bent on believing the projector a visionary, had nevertheless greatly puzzled the listener.