mineralogy. 
u 
With the acid of common fait they make 
a fal ammoniacum fixum, which alfo 
partly precipitates itfelf. 
c. The acid of nitre diflblves theni perfe6t- 
ly^ and does not part with them again, 
unlefs fome alcaline fait is added. 
6. They melt eafily with borax into a glafs, 
which fuffers impreffions in a degree of heat 
below ignition. 
7. They likewife fufe into a glafs with fal fu- 
fhile microcofmicum with an effervefcence 
8. They melt the readied: of all kinds of Hones, 
with the calces, into a corrofive glafs or 
flag. 
9. They have alfo fome power of reducing cer- 
tain metallic earths or cakes ; for inftance, 
thofe of lead and of bifmuth, and likewife, 
jthough in a lefs degree, thofe of copper and 
of iron : thus 
Ip. Do they, in this laft mentioned article 
(9.% as well as in other circumftances, re- 
femble a fixed alcaline falt^ from whence 
alfo this whole kind is very often, and pro» 
perly, called alcaline earths. 
ji. This whole order of earths is common to 
all the three kingdoms of nature ; bccaufe it 
is found in the bones and fhells of animals, 
as well as in the aflies of burnt vegetables 
it muft, confequ^ntly, have exifted before 
any living or vegetable fubftance ; and is, no 
doubt, proportionable to its univerfal ufe, 
diftributed throug}iout the whole globe. 
^ It is to be underftood, that this efFervefcence is alfo made 
with the borax, as well as with this Jalfufibile microcofmicum ; 
and it is alfo to be obferved, that the glaffes made with thefe 
falls are quite coiouriefs and tranfpVrent. 
SECT. 
