C 5^9 ] 
and then he purifyed the remainder by diHoIvIna It 
jn water, and by filtrating and evaporating the liquor 
and cryfialhfing the fait. 
After he had obtained the bafis of Tea fait quite 
pi.ie, e tiled a number of experiments with it, and 
vvnh the natron of Egypt ; and found that they ’were 
entirely of the fame nature, and that they were of a 
dilbnd. fpecies of alkaline fait, different in their pro- 
peities from the potafii, and other alkaline falts, 
commonly obtained by burning wood, and mofi; othei- 
vegetable fubflances ; and that they formed different 
neutral falts with the three mineral acids, and with 
the vegetable. 
Ijiis lalt U likewife got from burning the Barilla, 
the^Kah, and other marine plants ; and all that is at 
preient ulcd in tliis country, by our manufadurers, 
has been piepared in this manner. 
Hitherto it has not been found native in the 
we ern parts of Europe, except in mineral waters, 
und in the neighbourhood of volcanoes, or at places 
where they are alledged to have exifted formerly; 
but It has Jong been found in Egypt, and near to 
Smyrna, and in other eaftern countries, commonly 
mixed with earth, in a floury or concrete form ; in 
lome places pretty pure, in others more mixed (d). 
In the year 1764, a refpedable member of this 
Society Dr. \Vm. Heberden, gave an account of a fait 
of this kind, which was found on the Picof Tenerif 
where there is^ a volcano, and added feveral very 
ingenious experiments of the Honourable Henry Ca- 
(^) SeeHofFman. Phyf. Cher 
iVl^tcr. iV^ cd IC3 j p3.rt C3p« 
P'^S’ 55* 2 nd other authors. 
VoL. LXI. 4D 
lib. ii. obr. I. — GcofFroy, 
Shavv’s Travels, Excerp-t, 
vendifli. 
