334 
Mr. Davy’s Electrochemical Researches on 
Many difficulties however occurred in the way of obtaining 
complete evidence on this subject : and the pursuit of the en- 
quiry has required much labour and a considerable devotion 
of time, and has demanded more refined and complicated pro- 
cesses than those which had succeeded with the fixed alkalies. 
The earths like the fixed alkalies are non-conductors of elec- 
tricity ; but the fixed alkalies become conducting by fusion : the 
infusible nature of the earths, however, rendered it impos- 
sible to operate upon them in this state : the strong affinity 
of their bases for oxygene, made it unavailing to act upon 
them in solution in water; and the only methods that 
proved successful, were those of operating upon them by elec- 
tricity in some of their combinations, or of combining them at 
the moment of their decomposition by electricity, in metallic 
alloys, so as to obtain evidences of their nature and properties. 
Neuman’s Chem. Works, 2d. edit. vol. i. p. 15. The earlier English chemical phi- 
losophers seem to have adopted the opinion of the possibility of the production of 
metals from common earthy substances ; see Boyle, vol. i. 4to p. 564, and Grew, 
Anatomy of Plants, lec. ii. p. 242. But these notions were founded upon a kind of 
alchemical hypothesis of a general power in nature of transmuting one species cf 
matter into another. Towards the end of the last century the doctrine was advanced 
in a more philosophical form ; Bergman suspected barytes to be a metallic calx, Prasf. 
Sciagrap. Reg. Min. & Opusc. iv 21:. Baron supported the idea of the probability of 
alumine being a metallic substance, see Annales de Chemie, vol. x. p. 257.— La voisier 
extended these notions, by supposing the other earths metallic oxides. Elements, 2d 
edit. Kerr’s translation, p. 217. The general enquiry was closed by the assertion of 
Tondi and Ruprech t, that the earths might be reduced by charcoal ; and the accu- 
rate researches of Klaproth and Savaresi, who proved by the most decisive ex- 
periments, that the metals taken for the bases of the earths were phosphurets of iron, 
obtained from the bone ashes and other materials employed in the experiment, Annales 
de Chemie, vol. vlii p. 1 8. and vol. x. p. 25 7, 275. Amidst all these hypotheses, potash 
and soda were never considered as metallic in their nature; La voisi e r supposed them 
to contain azote ; nor at that time were there any analogies to lead that acute philo- 
sopher to a happier conjecture. 
