"There is a wonderful introduction to the first edition of the Sefer Yuchasin (Constantinople, 1566), printed from manuscript by the great scholar R. Samuel Shulam, which was omitted from all subsequent printed editions of the Yuchasin. In it I found the following: "Know that the author of the Yuchasin was greatly learned, expert in the entire Talmuds Bavli, Yerushalmi, Sifra, Sifre and midrashim. All were at this fingertips, which is evident to anyone who examines this book." [No one will dispute this--Rapoport] "He also composed another work, to complete that which the author the Aruch left incomplete. This extremely wonderful work can be found in Damascus. In addition to this wisdom, the author was in possession of immense knowledge of secular subjects, and a professor [a teacher in a cathedra, ie, professorial chair] at Salamanca, etc." Thus far the quote from Shulam's introduction."
"This wonderful writing also might be of great use, not only for his explanations of obscure words, but also in providing alternate readings of old books. See how many such readings are found in the Sefer Yuchasin, which are all worthy of great attention, as well as explanations he quotes from great scholars of the past. We know that he had before him a copy of the Aruch of Rav Zemach Ga'on [ie, which we do not possess]; who knows how many explanations from this same source are to be found in that wonderful expanded Aruch of his? Only 300 years have passed since this work was to be found in Damascus, and it's probably still there, or in its environs. It would be proper for learned travellers of the East to set their eyes and heart on this object, to inquire about it from all that love collecting old manucripts. Maybe one will come across it and make a copy and publish it to the joy of all who love learning!"
This excerpt gives a flavor of the time he was writing (1850s) when there was genuine cause for hoping that a book referred to 300 years earlier in a certain place was still there, could be obtained or copied and published.