I embrace this opportunity to bring a special plea to the notice of my readers. Having been compelled, by official duty, to be constantly absent from the place Where the printing of this work was going on, the cor rection of proof-sheets, which came to me, on my journeys in China, in an uncomfortably irregular manner, had to be done in a traveller's mood. I must therefore solicit the indulgence of my readers, with regard to the errors that have been overlooked at the proof-revisions.