102 On Mineralogical Surveys. [Fes. 
deserving individuals, in whose behalf Dr. Henry has so zealously 
appeared ; for the Doctor need not be told how many instances we 
have of chemical discoveries being made by persons at a distance 
from each other, and who had enjoyed no previous intercourse 
whatever. 
I cannot conclude this part of my reply without acknowledging 
the handsome manner in which Dr. Henry, in the supplement to 
his letter,* has spoken of my intentions; and I am confident that 
he will do me the justice to, believe that in this communication I 
have been actuated by no motive whatever except the desire of 
justifying myself both in his view and in that of the public. 
Respecting Mr. Thomas Henry, I am free to confess that I have 
not done him all the justice which I would have done had I been in 
possession of those facts which Dr. Henry’s letter now communi- 
cates. [have reason to believe that I had heard something of the 
exertions of Mr. Henry towards establishing the process in Man- 
chester ; but this was several years ago; and the matter was never 
in my recollection while writing the detail in which his name ought 
to have had a prominent situation, Jam the more surprised at my 
having thus forgotten Mr. Henry, when I perceive that I have 
spoken of him at p, 85 as the inventer of a method of bleaching 
the grounds of printed calicoes that have been dyed with madder, 
an invention of great importance, and which was afterwards com- 
municated by Berthollet to M. Obercamp, an eminent printer at 
Jouy, who embraced the proposal, and continued the practice ever 
afterwards. 
I trust, however, that Mr. Henry, whose very amiable character 
and eminent attainments in science have long secured for him the 
respect and esteem of all who know him, will not for a moment 
imagine that this great omission could have occurred from design ; 
and I now assure him that whenever there shall be occasion for a 
second edition of the Essays, none of his exertions for perfecting so 
important an art shall be left unrecorded. 
Tam, Sir, with great respect, 
Your most obedient humble servant, 
Groswell-street, London, SAMUEL PARKES. 
Jan. 6, 1816, 
ARTICLE ITI. 
On Mineralogical Surveys. By Robert Jameson, Esq. F.R.S. E. 
Professor of Natural History in the University of Edinburgh. 
(To Dr. Thomson.) 
DEAR SIR, 
Some time ago, at the desire of an accomplished and _ patriotic 
Nobleman, Lord Gray, I drew up the enclosed plan of a mineralo- 
* Annals of Philosophy for December, 1815, p, 472. 
ES eS eee ee 
i 
