He was not unfamiliar with the beautifully illuminated mediæval Arabic manuscripts. On one occasion, when looking over Silvestre’s “Universal Paleography” with myself, he remarked on the rare beauty of the Arabian illuminations, recalling his observation of them in an example shown to him in one of the mosques at Cairo; and he noted that even now illuminated manuscripts may be seen exposed for sale in the bazaars of Damascus and Grand Cairo. Dr. Porter referred to the great interest that he manifested in the work of the modern printing-press in the latter city, and the eagerness with which he inquired about the character of the books issued from the press set up there by the native Arabs. Dr. Porter told him “that there were many on medical subjects, many on interpretations of the Koran, on Mohammedan religion and morals, and one work especially which greatly pleased the common people.”--“What one is that?” he asked.--“The ‘Thousand and One Nights,’” was the reply. “You can hear them in every _café_ throughout the East. Men act them professionally, read and recite them; and those who frequent the _cafés_ always give them small presents in money.” The lack of a colloquial knowledge of the native language was a source of inevitable difficulty and trouble to the Spanish tourists; but in spite of this Mr. Nelson’s observant habits were directed to some of the local peculiarities of the native dialects, and Dr. Porter notes:--“He appeared to take a great interest in the language of that part of Spain which is to a large extent peopled by the descendants of the Moors. I told him of many of the local names which are derived from the Arabic, and gave him examples of the singular changes which have been made in them to give them a Spanish form and sound. ‘That accounts,’ he said, ‘for the peculiar pronunciation of some of those names by the people in the south of Spain, so very different from what would appear from the spelling, and from what we in this country have been accustomed to hear.’ He had noticed all this in his travels, and, as was his uniform habit, tried to get at the root of everything.”