eam Ts 
XVIII. On Symbolic Notation, as applied to Mineralogy. By 
H. J. Brooxs, Esq., F.R.S. F.L.S. £.G.S. 
To Richard Phillips, Esq. 
Dear Sir, 
HAVE, at the repeated solicitation of several of my friends, 
undertaken and made some progress in a new work on 
Mineralogy, in the course of which some difficulties have oc- 
curred relative to the chemical constitution of minerals and 
their distribution into species, which perhaps some of your 
chemical readers may assist in removing; and on this account 
I shall feel obliged by an early insertion of this notice in your 
Journal. 
Before I commenced the work in which I am engaged, I 
had thought of proposing a new edition of the late W. Phil- 
lips’s useful volume; but upon a close examination of its con- 
tents I found it would require so much correction, and so great 
a remodelling, to adapt it to the present state of mineralogical 
knowledge, that it would be less troublesome to prepare a new 
treatise. 
Notwithstanding the decided objection entertained by you 
to the use of symbols, I am disposed to regard them as very 
serviceable in ceconomizing time and labour ; and it will pro- 
bably turn out that your objection applies rather to the unne- 
cessary and capricious changes to which these short-hand 
characters have been subjected, and their employment in the 
expression of conflicting theories, than to the characters them- 
selves. 
Symbols were first introduced by Berzelius, which fully 
answered the purpose for which they were intended; and it 
would have been much better, and much confusion would have 
been spared, if they had been rigidly adhered to, notwith- 
standing any slight improvement of which they might have 
been susceptible. But, unfortunately, in the symbolical repre- 
sentations of the composition of minerals published by dif- 
ferent authors, not only are the symbols of Berzelius changed, 
but the formule are made up according to the peculiar views 
of each author concerning atomic weights, and their several 
notions of the most fit manner of parcelling out into definite 
compounds such of those constituents of a mineral, as given 
by analysis, as they choose to consider essential to its constitu- 
tion, after having rejected whatever they imagine to be foreign 
matter. 
These differences will be apparent on a comparison of the 
analyses of different minerals, as given by Leonhard in his 
Handbuch der Oryctognosie, and by Thomson in his recently 
