Those metallic bodies we are at present acquainted with, and which we can reduce to the metallic or reguline state, are the following seventeen:
1. Arsenic. 2. Molybdena. 3. Tungstein. 4. Manganese. 5. Nickel. 6. Cobalt. 7. Bismuth. 8. Antimony. 9. Zinc. 10. Iron. 11. Tin. 12. Lead. 13. Copper. 14. Mercury. 15. Silver. 16. Platina. 17. Gold.
I only mean to consider these as salifiable bases, without entering at all upon the consideration of their properties in the arts, and for the uses of society. In these points of view each metal would require a complete treatise, which would lead me far beyond the bounds I have prescribed for this work.
[30] I have not ventured to omit this element, as here enumerated with the other principles of animal and vegetable substances, though it is not at all taken notice of in the preceding chapters as entering into the composition of these bodies.--E.
[31] Perhaps my thus rejecting the alkalies from the class of salts may be considered as a capital defect in the method I have adopted, and I am ready to admit the charge; but this inconvenience is compensated by so many advantages, that I could not think it of sufficient consequence to make me alter my plan.--A.
[32] Called Alumine by Mr Lavoisier; but as Argill has been in a manner naturalized to the language for this substance by Mr Kirwan, I have ventured to use it in preference.--E.
_Continuation of the Observations upon Salifiable Bases, and the Formation of Neutral Salts._
It is necessary to remark, that earths and alkalies unite with acids to form neutral salts without the intervention of any medium, whereas metallic substances are incapable of forming this combination without being previously less or more oxygenated; strictly speaking, therefore, metals are not soluble in acids, but only metallic oxyds. Hence, when we put a metal into an acid for solution, it is necessary, in the first place, that it become oxygenated, either by attracting oxygen from the acid or from the water; or, in other words, that a metal cannot be dissolved in an acid unless the oxygen, either of the acid, or of the water mixed with it, has a stronger affinity to the metal than to the hydrogen or the acidifiable base; or, what amounts to the same thing, that no metallic solution can take place without a previous decomposition of the water, or the acid in which it is made. The explanation of the principal phenomena of metallic solution depends entirely upon this simple observation, which was overlooked even by the illustrious Bergman.