96 
which I have called photogenic drawing-paper, consequently, the 
Jinal results of the two processes cannot anyhow be distinguished. 
I thank you for your courtesy in mentioning that you are about 
to send a Paper on the subject to the Royal Irish Academy by the 
hands of Dr. Robinson. May I request that this letter and my 
former one, with the permission of the Academy, may be read to 
them on the same occasion, if Dr. Robinson will kindly take charge 
ofthem. It may be left to their scientific judgment to say whether 
a new principle is iny olved or not in your experiments. If any 
new principle be involved, then a distinctive name, such as you 
have given, is, of course, desirable,—otherwise it would not be so. 
I would refer also to the instance of the Daguerreotype, now so dif- 
ferently managed from what it used to be at the time of its first 
promulgation. It is now at least a hundred times more rapid in 
its effects, but it still continues to be called the Daguerreotype. 
On the other hand, I believe it is not affirmed that any process on 
paper has been discovered more rapid or more certain than the 
Calotype; I am not aware of any such having been as yet described. 
We should certainly be very grateful to any one who discovered a 
more rapid process, depending on new combinations; but if I do 
not err in defining the Calotype process as depending on a combi- 
nation of iodine, silver, and a deoxydising agent, your process 
would be included in that definition, unless good reasons to the 
contrary could be shewn, all which I willingly leave to the judg- 
ment of the scientific world: and, thanking you for your polite 
attention in so soon answering my last letter, 
*¢ T remain, Sir, 
** Your’s very truly, 
‘** H. Fox Tarror. 
“« P,S.—If your process does anything which the Calotype can- 
not do, or does it better, I willingly admit its importance; but I 
apprehend that you are not aware of the facility and rapidity with 
which our Calotype operations are now conducted. Indeed, that 
was my chief reason for troubling you with a letter, as your Paper 
read at the York meeting mentioned the spontaneous development 
of photogenic images as something new, whereas it is a phenomenon 
