Dr Daubenj mi separating Lime from Magnesia* SIT 
were only as cautions to those who may employ these reagents 
in precipitating magnesia from its solutions. 
The objections that have been raised against these, do not ap- 
ply to Dr Wollaston’s plan of converting the earth into a triple 
phosphate with ammonia, as the peculiar tendency to form triple 
salts, which renders the precipitation of magnesia from its solu- 
tions in other cases imperfect, is here beautifully employed to 
serve the very purpose of separating it from other earths. This 
latter circumstance, as well as the insolubility of the precipitate 
thus obtained^, gives this method of analysis a decided superio- 
rity over that by the pure alkalies or their subcarbonates. 
And now having brought to a conclusion my remarks on the 
methods of separating magnesia from lime, it only remains for 
me to apologize for the length to which this part of my paper 
has extended. Had I, indeed, consulted my own ease and that of 
my readers, I should have, undoubtedly, contented myself with 
merely stating the results to which my enquiries had led, with- 
out entering into the detail of the experiments themselves - a 
mode which, whilst it enabled me to compress my materials in- 
to a narrower compass, would have laid me much less open to 
criticism? than the plan I have chosen to adopt. I felt, however, 
that (particularly in the first chemical paper I ever presented to 
the public) I had no right to expect that other persons should 
take for granted my conclusions, unless satisfied as to the road 
by which I had arrived at them, and enabled fully to judge for 
themselves, how far the several steps of this inquiry have been 
correct, and in what respects they may have diverged into error. 
Art. XIX. — Account of The Jeffersonite^ a new Mineral dis~ 
covered at the FranMine Iron- Worhs^ near Sparta., New- 
Jersey. Described and analysed by William H. Keat- 
ing, Member of the Wernerian Society. 
About six miles to the north-east of the town of Sparta, in 
Sussex county, New-Jersey, are to be seen the remains of the 
old Franklin furnace. This furnace, situate on one of the most 
* Both magnesia and its carbonate are soluble in water, as is proved by Dr 
Fyfe in the Edin. Jour, vol. vi. 
