Read it through once

"I have studied some of these signatures so much that I know them as well as the bank cashier knows the autograph of his oldest customer. While I turn my back now, I beg that several persons will be so good as to pass their fingers through their hair, and then press them upon one of the panes of the window near the jury, and that among them the accused may set their finger-marks. Also, I beg that these experimenters, or others, will set their finger-marks upon another pane, and add again the marks of the accused, but not placing them in the same order or relation to the other signatures as before--for, by one chance in a million, a person might happen upon the right marks by pure guess-work once, therefore I wish to be tested twice."