Dr, Wall on the UJe of Symbols. 
243 
Conjectural Remarks on the Symbols or Charac¬ 
ters, employed by Astronomers* to reprefent 
the feveral Planets, and by the Chemists, to 
exprefs the feveral Metals, in a Letter to 
Thomas Percival, M. D. F. R. S. &c. By 
Martin Wall, M. D. Pra.leClor of Chemiftry 
in the JJniverfity of Oxford. Read October 9, 1782. 
S I R, 
I AM extremely apprehenfive, left the following 
obfervations, as relating to a fiibjeCt more 
fpeculative than ufeful, may be thought unwor¬ 
thy of the attention of your very refpeCtable 
Society; yet, defirous to ftiew my juft fenfe of 
the compliment, which you have paid me, by 
propofing me as an honorary member, I advance 
them with great deference, hoping you will fup- 
prefs them entirely, if they fhould not meet the 
approbation of your correCt judgment. 
Whoever engages in the ftudy of Chemiftry, 
cannot but remark, with fome degree of curiofity, 
how extenfively the ufe of fymbols or characters 
has prevailed in this fcience; and is naturally 
led to enquire, from whence this practice origi¬ 
nated, and whether the characters ufcd arc 
merely arbitrary, or have any relation, real or 
R 2 imaginary, 
