[ 5^8 ] 
The knowlege of it was entirely loft for feveral 
centuries, but was revived in the laft, by the Ho- 
nourable R. Boyle, formerly a diftinguifhed member 
of this Society, who, in his Short Memoirs for the 
natural experimental Hiftory of Mineral Waters (c), 
after telling us that it is of an alkaline nature, fays, 
“ that he had fome of it brought from iEgypt, and 
“ a neighbouring country, whofe name he did not 
" remember.” 
However, it was afterwards negleded, and its 
properties as a diftindl fpecies of alkaline fait not 
known for many years j for although chemifts^ ob- 
ferved,. that a Glauber fait -and cubic nitre were 
. formed by diflodging the marine acid from fea fait, 
by means of the vitriolic and nitrous acids ; and from 
thence fufpedfed that there was fomething particular 
in the bafis of this fait i yet its true nature was not 
difeovered till Monf. du Hamel du Monceau gave an 
account, in the Memoirs of the French Royal Aca- 
demy of Sciences for the year 1736, of his having 
obtained it pure, in two different ways, ift, By 
diflodging the marine acid by means of the vitriolic, 
and then feparating it by the addition of a phlogifton, 
and forming a hepar fulphuris, from which he pre- 
cipitated the furphur by means of the vegetable acid, 
and then feparated this acid from the bafls of fea fait 
by the force of fire., adly. By diflodging the marine 
acid from the fea fait by the addition of the nitrous, 
and fo forming a cubic nitre, from which he dif- 
lodged the acid, by deflagrating it with charcoal j 
(c) See bis Notej on Title a6, page 86, of the edition printed 
at London 
and 
