The fourth phenomenon is, that metals are absolutely insoluble in such acids as have their bases joined to oxygen by a stronger affinity than these metals are capable of exerting upon that acidifying principle. Hence silver, mercury, and lead, in their metallic states, are insoluble in muriatic acid, but, when previously oxydated, they become readily soluble without effervescence.
From these phenomena it appears that oxygen is the bond of union between metals and acids; and from this we are led to suppose that oxygen is contained in all substances which have a strong affinity with acids: Hence it is very probable the four eminently salifiable earths contain oxygen, and their capability of uniting with acids is produced by the intermediation of that element. What I have formerly noticed relative to these earths is considerably strengthened by the above considerations, viz. that they may very possibly be metallic oxyds, with which oxygen has a stronger affinity than with charcoal, and consequently not reducible by any known means.
All the acids hitherto known are enumerated in the following table, the first column of which contains the names of the acids according to the new nomenclature, and in the second column are placed the bases or radicals of these acids, with observations.
_Names of the Acids._ _Names of the Bases, with Observations._
3. Phosphorous }Phosphorus. 4. Phosphoric }
5. Muriatic }Muriatic radical or base, hitherto unknown. 6. Oxygenated muriatic }
7. Nitrous } 8. Nitric }Azote. 9. Oxygenated nitric }
}The bases or radicals of all these acids 11. Acetous }seem to be formed by a combination 12. Acetic }of charcoal and hydrogen; 13. Oxalic }and the only difference seems to be 14. Tartarous }owing to the different proportions in 15. Pyro-tartarous }which these elements combine to form 16. Citric }their bases, and to the different doses 17. Malic }of oxygen in their acidification. A 18. Pyro-lignous }connected series of accurate experiments 19. Pyro-mucous }is still wanted upon this subject.
20. Gallic }Our knowledge of the bases of 21. Prussic }these acids is hitherto imperfect; we 22. Benzoic }only know that they contain hydrogen 23. Succinic }and charcoal as principal elements, 24. Camphoric }and that the prussic acid contains 25. Lactic }azote. 26. Saccholactic }