On a Series of Lantern Slides. By Dr. A. Clifford Mercer. 309 
chemically the same. The important question was “ When was the 
erasure made ? ” The holder, Mr. Lewis, was almost alone in saying 
the erasure was made when the note was drawn. Finally, the 
Microscope was brought into service. 
Slide 26 (plate IV. fig. 10) shows in part what the Microscope 
revealed. The letter a of “ bearer ” and a portion of the lines of erasure 
are seen. The ink of the cross-lines has partially overflowed to the 
lines of the letter. Therefore, the erasure was made before the words 
“ or bearer ” were quite dry ; and as the note did not reach Mr. 
Lewis for nine months after it was made, the erasure could not have 
been made by Mr. Lewis. But even this result did not quite satisfy 
the plaintiffs counsel, Mr. J. T. Newman, of Ithaca, N.Y. He 
wished to have the time of the erasure more definitely fixed. The 
Microscope succeeded at last in satisfying the counsel, by approxi- 
mately fixing the time. This was done in the following manner. 
It was noted that in the erasure of the words “ or bearer ” the cross- 
lines gave a possibility of 52 overflowings and that there were actually 
28 overflowings to a degree as great as, or greater than, a certain 
overflowing taken as a standard unit ; that is to say, the actual 
overflowing was 54 per cent, of the possibility. The words “ or 
bearer” were then repeatedly written and crossed at different intervals 
of time afterward. A series of such erasures with an interval of five 
hours gave • 0 per cent, of overflowing. A series with an interval of 
one hour and a series with an interval of fifteen minutes both gave 
•0 per cent, of overflowing. A series with an interval of five 
minutes gave • 8 per cent, of overflowing. A series with an interval 
of three minutes gave • 4 per cent, of overflowing. A series with an 
interval of two minutes gave 1 • 1 per cent, of overflowing. A series 
with an interval of one minute gave 17 per cent, of overflowing. A 
series with an interval of 1 /2 minute gave 35 per cent, of overflow- 
ing. A series with an interval of only a few seconds gave 90 per 
cent, of overflowing. As the supposed conditions under which the 
note had been made were imitated in getting the foregoing per- 
centages and as the erasure in the note had given 54 per cent, of 
overflowing, it was reasonable to believe the erasure was made ap- 
proximately within half a minute after the words “ or bearer ” were 
written, an interval of time shown by experiment to be little more 
than enough for writing the remainder of the note and signing it. 
The Microscope, then, was able to show that the erasure was not only 
made before the words “ or bearer ” were dry, but at the latest almost 
immediately after the note was signed. Slides 28 and 29 are photo- 
micrographs of experimental cross-lines over l of “ Charles ” and 
d of “ dollars ” in the note (plate 1Y. fig. 9). The ink of the 
cross-lines has not overflowed to the lines of the letters. 
The case was argued before a referee, J. N. Hammond, Esq., in 
Seneca Falls, N.Y. , June 25th, 1887, and, notwithstanding the weight 
of other evidence favoured the defendant, the Microscope in the court, 
