128 Mr. Hatchett’s Analysis of the earthy Substance 
by analysis, a portion of the same earth on which Mr. Wedg- 
wood made his experiments, and as I received it from Sir 
Joseph Banks, the same gentleman who had furnished Mr. 
Wedgwood with it, no suspicion can be entertained about its 
identity. 
Some of the experiments which I have related, and which 
prove that some of the finer earthy particles remained suspended 
in the concentrated muriatic acid, and were precipitated when 
the acid was diluted with water, appear in some measure to ac- 
count for the mistake which has been made, in supposing that 
a primitive earth, before unknown, was present ; but this alone 
will not account for many of the other properties mentioned by 
Mr. Wedgwood, such as, 
ist. The repeated and exclusive solubility in the muriatic 
acid, and subsequent precipitation by water. 
2dly. The butyraceous mass which was formed by evapo- 
ration. 
And, 3dly. The degree of fusibility of the precipitated earth. 
These indeed I can by no means explain, but by supposing 
that the acids used by Mr. Wedgwood were impure. This 
supposition appears to be corroborated by a passage in Mr. 
Wedgwood’s paper, where he says, “ here the Prussian lixi- 
“ vium, in whatever quantity it was added, occasioned no pre- 
“ cipitation at all, (only the usual bluishness arising from the 
iron always found in the common acids.”)* Now if (as it 
seems from this expression) Mr. Wedgwood employed the 
common acids of the shops, without having previously exa- 
mined and purified them, all certainty of analysis must fall, 
as the impurity of such acids is well known to every practical 
* Philosophical Transactions, Vol. LXXX. Part II. p. 313. 
