250 Dr. Hare on the Chemical Nomenclature of Berzelius. 
posé d’un combinaison binaire appelleé base et un autre combi- 
naison binaire appelleé acide. Les sels dit haloide, ne sont pas, 
d’apres vous, des sels, puis qu’ils ne sont. compose que de deux 
elements et ne contienent ni base ni acide.” That this account of 
my Opinion is erroneous must appear from the following language, 
held in my letter to Prof. Silliman, which first gave rise to our 
correspondence on the subject of screenees 
“The most striking feature in the nomenclature of Boivolide 
is the formation of two classes of bodies, one called ‘ halogene,’ 
or salt producing, because they are conceived to produce salts di- 
rectly ; the other ‘amphigene,’ or both producing, being pro- 
ductive both of acids and bases, and of course indirectly of 
salts. To render this division eligible, it appears to me that the 
terms acid, base, and salt, should, in the first place, be strictly de- 
fined. Unfortunately, there are no terms in use, more broad, 
vague, and unsettled in their meaning. Agreeably to the com- 
mon acceptation, chloride of sodium is pre-eminently entitled to 
be called as a salt ; since in common parlance, when no distin- 
suishing term is annexed, salt is the name of that chloride. This 
is quite reasonable, as it is well known that it was from this 
compound, that the genus received its name. Other substances, 
having in their obvious qualities some analogy with chloride of 
sodium, were, at an early period, readily admitted to be species 
of the same genus; as for instance, Glauber’s salt, Epsom salt, 
sal-ammoniac. Yet founding their pretensions upon similitude 
in obvious qualities, few of the substances called salts, in the 
broader sense of the name, could be admitted. into the class. 
Insoluble chlorides have evidently, on the score of properties, as 
little claim to be considered salts, as insoluble oxides. Luna 
cornea, plumbum corneum, butter of antimony, and the fuming 
liquor of Libavius, are the appellations given respectively to chlo- 
rides of silver, lead, antimony, and tin, which are quite as defi- 
cient of the saline character as the corresponding compounds 
of the same metal with oxygen. Fluoride of calcium (fluor spar) 
is as unlike a salt as lime, the oxide of the same metal.” 
‘On the other hand, if instead of qualities, we resort to compo- 
sition as the criterion of a salt; if, as in some of the most re- 
spectable chemical treatises, we assume that the word salt is to 
be employed only to designate compounds consisting of a base 
united with an acid, we exclude from the class chloride of sodium, 
