Classification of simple Bodies. 445 
which shall be developed and defined in the two following arti- 
cles. The bodies which have been hitherto considered as non- 
metallic, all possess the property of forming acids with some 
among them, the distinctive character of which is to make acid 
all combinations into which they enter in sufficient quantity. 
Several metals, and even some of those best entitled to this 
name, also present this property, and produce acids on being 
combined with the same acidifying substances. Those metals 
form two groupes, distinguished besides from each other by nu- 
merous differences. Some are eminently fixed and infusible; and 
it seems to be the same case with their combinations with chlore, 
at least if we may judge by the chlorure of chrome which presented 
this property to M. Dulong. It is with oxygen that they produce 
the acids from which the chemists have drawn the character which 
distinguishes them. The others are very fusible ; the combina- 
tions which they form with oxygen present but feeble acid cha- 
racters; fur we ought not to reckon among them arsenic, which, 
as I have already said, ought to be united to the bodies which are 
considered as not metallic. And but for the labours of Messrs, 
_ Chevreul and Berzelius, the acidity of the peroxides of tin and 
antimony would have been still unknown; but these metals pro- 
duce with chlore compounds liquid, or of a butyraceous consist- 
ency and volatile, and which possess the most essential properties 
of the acids. It is easy to see that the non-metallic simple 
bodies are united on the one hand with the infusible metals 
acidifiable by carbon and borium, and on the other with tin 
and antimony by phosphorus and arsenic, the combinations of 
which with chlore have the greatest analogy with the chloro- 
stannic acid (spiritus Libavii). All the other metals ought 
therefore to be placed between tin and antimony on the one 
hand, and the infusible acidifiable metals on the other. Those 
which add to the greatest affinity for oxygen, the property of 
forming with it alkaline combinations, occupy in some measure 
the middle part of this interval, and are connected on the one 
hand with tin and antimony, and on the other with tungsten, 
columbium, chrome, and molybdenum, by two series of metals, 
which present in the one and the other series all the degrees of 
affinity for oxygen, and the oxides of which also pass gradually 
through the various degrees of alkalinity and acidity which cha- 
racterize that kind of compounds; but the bodies of which the 
two series are composed, present besides sufficient differences-to 
enable us always easily to determine that to which they belong. 
Such is theorder by which I have been led, not. by systematic 
views, which I disavow; but after having made a great number 
of attempts, in order to see if we could not adopt another with- 
' out 
