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At this stage of the inquiry I should like to ask a question 
of those who have inspected a large number of these pictures. 
Do any of them show unmistakeable marks of the originals, 
such as we are all familiar with in photographic copies ? If 
this could be favourably answered, then photography of the 
present day would be benefited by the discovery of the means 
adopted in fixing these pictures. I much doubt if one of our 
best photographs on paper would contrast favourably with 
these pictures in the whites after a lapse of seventy years. 
But in my humhle opinion photography has not been the 
agent employed in producing these pictures. 
Mr. Sidebotham had a portion of one picture presented to 
him, and he kindly shared this with me. In my experiments 
I found that the colouring matter forming the picture could 
be washed off like ordinary ink, without leaving a trace of 
any chemical action on the paper. Now if this portion of 
the picture be a genuine sample, it does not exhibit the ordi- 
nary characteristics of a photograph. 
On further consideration there are many reasons which 
would lead me to conclude that these pictures have been 
produced by some modification of mezzotint engraving, in 
which the camera had enabled the engraver to trace his out- 
line from the original to any scale required, giving him the 
correct outline drawing, the shading being an after process ; 
but the rapidity of production, and the low price charged, 
unfortunately excludes this process from the list of probabili- 
ties. Although mezzotint is said to be the most rapid method 
of engraving, I am compelled to abandon it or its modifica- 
tions, and pass on to some other process. 
Now if we do not believe in the photographic portion of 
the secret, and are not permitted to employ engraving on 
metal on account of the expense and labour, we find the field 
of speculation becoming somewhat limited. 
Now comes a very important question : — Did Mr. Boulton 
anticipate Senefelder in some process similar to lithography, 
employing metallic plates or metallic alloys ? I can almost 
