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SECT. LVL 
A traveller, who has feldom an opportunity of 
carrying many things along with him, may very 
well be contented with this Pocket-Laboratory, 
and its apparatus, which is fufficient for moft part 
of fuch experiments as can be made on a journey. 
There are, however, other things very ufeful to 
have at hand on a journey, which ought to make 
a fecond part of the Pocket-Laboratory, if the 
manner of travelling does not oppofe it : this con- 
fifts of a little box including the different acids, 
and one or two matraffes, in order to try the minC’ 
ral bodies in liquid menftrua, if required. 
SECT. LVIL 
Thefe acids are, the Acid of Nitre, of Vitriol, 
and of Common Salt, Moft of the ftones and 
earths are attacked, at leaf: in fome degree, by the 
acids *, but the calcareous are the eafieft of ail to be 
diffolved by them, which is accounted for by their 
calcareous properties. The acid of nitre is that 
which is moft ufed in thefe experiments; it dif- 
folves the limeftone, when pure, perfedly, with a 
violent effervefcence, and the folution becomes 
clear : when the limeftone enters into fome other 
body, it is neverthelefs difeovered by this acid, 
through a greater or lefs effervefcence in proportion 
to the quantity of the calcareous particles, unlefs 
thefe are fo few, as to be almoft concealed from the 
acid by the heterogeneous ones. In this manner, 
a calcareous body, which fometimes nearly refem- 
bles a filiceoiis or argillaceous one, may be known 
from thefe latter, without the help of the Blow-pipe, 
only by pouring one or two drops of this acid 
upon 
