4 
a 
| Method of preparing Sai A etatus. 38 
' 4 the open air, and, for all common purpofes, is, I believe, 
®qual to that prepared by cryftallifation. 
Note. The pearl-afhes had better be put into the box ia 
™moderate-fized lumps than in powder, that the air may have 
free accefs to it. 
But if any choofe to have this falt in its moft perfect form, 
jet him proceed in this manner : 
Diffolve as much of the clean vegetable alkali. in boilmeg 
rai or other pure water as poffible; filter the folution 
‘through paper, pour it into a jar of {tone or earthen-ware, | 
‘cover the veffel in fuch a manner as that the air may ‘have 
accefs to it, but fo as to exelude all duft or foreign matter 
Let it be hung by a cord in a fermenting vat, or ciftern, for 
‘a month or two, in which time a great many cryftals will be 
formed; from which the fuperfiuous liquor may be :poured 
off, and the falt dried in Hippocrates’ fleeve. The fuper- 
fluous liquor may be again faturated with more alkali, and 
again uxpofed tothe air in the ciftern, without any lofs.. This 
‘laft is, without doubt, the moft perfect mode of preparation, 
and I have fometimes made afe of it; but, as it is much 
more troublefome to make than the other, and as the other, 
‘for all medicinal susrdees is perhaps equal 'to'this, I have 
for the moft part mar loyed ‘it. 
This fait is much more tolerable to the palate, and may 
de taken in larger dofes than the naked alkali ; and as it is 
.decompounded by vegetable acids \as well as the mineral, it 
may be exhibited infiead of the alkali .in perhaps every cafe 
where the latter is proper, unlefs the fixed air is judged -im- 
»proper. 
It is much fuperior to common alkali in forming Riverius’s 
anti-emetic effervefcing draught, as it contains a iio larger 
"proportion of fixed air, (in which the principal virtue-of that 
medicine is fuppofed to refide) than the mildeft fixed alkali, 
and is at the fame time much more palatable. 
I commonly direét about 3 ii, or rather more, of this falt 
‘to be diffolved in 3 iii of fair water; a large fpoonful of this 
folution, added to the fame quantity of good vinegar, or 
Jemon-juice, at the inftant of {wallowing it, makes an agree- 
~~ -able dofe. But the tafte of this folution is fo mild, that, if 
: ro) the 
