Some correspondents ask me if I believe that all pretensions to intercourse with departed spirits are impositions. I reply, that if people declare that they privately communicate with or are influenced to write or speak by invisible spirits, I cannot prove that they are deceived or are attempting to deceive me--although I believe that one or the other of these propositions is true. But when they pretend to give me communications from departed spirits, to tie or untie ropes--to read sealed letters, or to answer test-questions through spiritual agencies, I pronounce all such pretensions ridiculous impositions, and I stand ready at any time to prove them so, or to forfeit five hundred dollars, whenever these pretended mediums will succeed in producing their "wonderful manifestations" in a room of my selecting, and with apparatus of my providing; they not being permitted to handle the sealed letters or folded ballots which they are to answer, nor to make conditions in regard to the manner of rope tying, etc. If they can answer my test-questions relevantly and truly, without touching the envelopes in which they are sealed--or even when given to them by my word of mouth, I will hand over the $500. If they can cause invisible agencies to perform in open daylight many of the things which they pretend to accomplish by spirits in the dark, I will promptly pay $500 for the sight. In the mean time, I think I can reasonably account for and explain all pretended spiritual gymnastic performances--throwings of hair-brushes--dancing pianos--spirit-rapping--table-tipping--playing of musical instruments, and flying through the air (in the dark,) and a thousand other "wonderful manifestations" which, like most of the performances of modern "magicians," are "passing strange" until explained, and then they are as flat as dish-water. Dr. Von Vleck publicly produces all of these pretended "manifestations" in open daylight, without claiming spiritual aid. Among the number of humbugs that owe their existence to various combinations of circumstances and the extreme gullibility of the human race, the following was related to me by a gentleman whose position and character warrant me in announcing that it may be implicitly relied upon as correct in every particular.