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the same subject such minute lines and marks are found to 
exist in both — lines not visible without the microscope, quite 
impossible to be copied by hand. Besides, Ave have the tes- 
timony of those whose lives have been spent in engraving and 
making facsimile productions that the thing is impossible. 
They could not, I think, be impressions from metal or blocks. 
The peculiar surface of the paper, and the colouring matters 
used, Avould be quite unsuited to printing purposes. The 
great cost of engraving these large surfaces for but a limited 
number of copies ; the different sizes in which the pictures 
could be made; the non-necessity, in such case, for the 
reversing of the pictures — are all good arguments against any 
system of engraving being used. 
It has been said that the plate mark on some of the pic- 
tures suggests the employment of plate printing; but, on 
examination, as you will see, the supposed plate mark is 
merely an embossed line on the paper, either intended as a 
finish or, more probably, to mislead as to the mode of 
production. 
The specimens for your examination consist — 
1st. Of two similar pictures — one plain, the other coloured. 
A careful examination of these will show that spots and lines 
only visible Avith a lens exist exactly the same in each, such 
as no artist could possibly copy ; yet, strange to say, there are 
considerable differences — some of them striking; but these 
are of precisely the same nature as you would have in an 
under-exposed and an over-exposed print, both from the same 
negative. 
2nd. We have a coloured mechanical picture — subject, 
The Graces Awakening Cupid. This may be compared with 
an engraving of the same subject, evidently both taken from 
the original painting. In this you will notice the mechanical 
picture is reversed. 
3rd. We have a red mechanical picture — Flora Bedecking 
Pan. This may also be compared Avith an engraving of the 
