Dr. withering on- the 
3 
to DR. PRIESTLEY, 
S I Iv 9 ... Birmingham, 
March 2 S, 1782. 
I NOW lend you the remits of my examination of the 
1 oad-done and the Rowley- rag-flone ; being part of a plan 
wiiieh I have long lince formed for a chemical analyfis of all 
the iubftanccs that are known to exid in the earth in large 
quantitv. 
X <J 
Some years ago I tranfmitted to the Royal Society an analyfis 
of the different marles found in Staffordfhire, which they did 
fne the honour to infert in their Tranfa&ions ; if they think 
thefe papers likewife worth their adoption, f {hall fend them 
the remits of my future inquiries. 
In the conrfe ot experiments which this fubjeft has led me 
to, 1 found it convenient to form fome new tables, and to en- 
large fome that were lefs completely formed before. Thefe 
tables will be ufeful in other branches of chemical inquiry. 
One of them I fubjoin to the prefent papers. The fads taken 
from M. macq^jer are marked with an m ; thofe with the * 
are tiie confequeiice of my own experiments. 
In order to lave much repetition in future, it may not be 
amifs to mention, once for all, a few particulars in the condudl 
of thefe proceffes. 
1 If, By •water , is always meant water diddled in glafs vel* 
Ids, or by means of a large tin refrigeratory in Mr. irwin’s 
method. 
adly. Only glafs or chilla velTels are ufed in the liquid 
precedes. 
qdly, By a mortar I mean thofe excellent ones made by 
Mr. wedgewood ; or, as will be fpecihed at the time, a deel 
mortar 
