7 
1811.) 
es TOPOGRAPHY. 
Notices respecting Jamaica, in 1808, 9, and 
40. By Gilbert Mathison, esq. 5s. 
» An Account of the past and present State 
ef the Isle of Man. 8vo. 10s. 6d. 
VOYAGES AND TRAVELS. 
Travels in the Spanish Provinces of Anda- 
Proceedings of Learned Societies. 
455 
lusia, Granada, Murcia, Valencia, and Catae 
lonia, up to. Montserrat, and also in Mae 
jorca and Minorca, during the year 1609, 
By Sir John Carr. 4to. 21. 2s. 
A General History and Collection of 
Voyages and Travels. By Robert Keszy 
F.R.S, F.A.S. Edin. Part ILL, 6s. 
PROCEEDINGS OF LEARNED SOCIETIES, 
————— 
ROYAL INSTITUTION. 
EW discoveries in modern times 
have so powerfully excited the at- 
tention of the scientific world, as that of 
the metallic nature of potass, soda, and 
ammonia; though this discovery has not~ 
hitherto been attended with any benefi- 
cial practical application. It can how- 
ever scarcely be doubted, that a more 
perfect acquaintance with the nature of 
metallic bodies, must be followed by im- 
proved processes in the modes of smelt- 
ang the ores, and in the various arts of 
metallurgy. Potassium, or the metal of 
potass, has lately been procured in larger 
quantities, by heating iron fileings and 
potass together in a gun barrel, or iron 
retort coated with clay. The colour of 
potassium resembles that of tin, it is ea- 
sily cut with a knife, and solders with it- 
self at the common temperature of the 
atmosphere. Its most remarkable quali- 
ties are its levity and combustibility. It 
is considerably lighter than water; if the 
weight of a given quantity of water were 
10 oz. that of the same quantity of pot- 
assium would be only 7 oz. it is the 
lightest knowa solid substance. Wher it 
comes in contact with water, it imme- 
diately inflames with great violence, de- 
composing the water and absorbing its 
oxygen. It will burn with intense heat 
and vivid light under the surface of wa- 
ter, and will probably be found the most 
powerful agent in destructive naval war- 
fare, that has ever heen employed. The 
properties of sodium are nearly similar to 
those of potassium; except that when 
pure it does not inflame with water, but 
moves in @ rapid manner along its sur- 
face, decomposing it, and absorbing the 
oxygen. Potass, or the vegetable alkali, 
im the purest state in which it is obtained 
by chemical means, retains 17 per cwt. 
of water, even after being kept in a red 
heat for several hours; it is properly an 
hydralt of potass. When potassium is 
burned in oxygen gas, it forms a sub- 
ptance containing more oxygen than pote 
ass, and is free from water; it is hard 
aud abagst infusible; but when it has 
wu! 
parted with some-of its oxygen and aes 
quired a portion of water, it has all the 
properties of potass. Ammonia has only 
been procured as a metallic amalgam, 
united with mercury, or sodium. The 
manner of procuring it is, by placing a 
globule of mercury in a small cavity, 
made in a piece of muriat of ammonia, 
(sal ammonia) one wire from a voltaig 
battery is connected with the mercury, 
the other with the muriat of ammonia’ 
the globe of mercury is increased in size, 
loses its fluidity, and becomes a solid me- 
tallic amalgam. 
The discovery of the metallic nature of 
the alkalies, potass, and ammonia, has 
been followed by the discovery, that‘ath 
the earths are also metals united with 
oxygen. These earths are silex, clay, 
lime, magnesia, barytes, strontian, and 
the newly discovered earths, zucon, uriay 
and glucine. 
Lavoisier in his: elements states his 
opinion that barytes, and some if not all 
the earths were metallic oxyds, but this 
opinion was not supported by any proof; 
and the experiments of Tondi, who ase 
serted that he had procured globes of 
metal from barytes, lime, and magnesia, 
have generally been regarded as incone 
clusive, but perhaps they have not been 
properly investigated.* By means of the 
Voltaic battery, Dr. Davy procured very 
small globules of metal from all the 
earths, but they explode almost imme. 
diately after their-formation, and absorb 
oxygen from the water, which is used to 
make the earths into a paste to be acted 
upon by the Voltaic battery in these exe 
periments, Potassium, or the metal from 
potass, has the strongest athnity for oxy- 
gen of all known substances; when it is 
combined with the earths, and acted 
upon by the Voltaic battery, a larger 
globe of metal may be obtained from 
them. The attempt to decompose the 
earths by ignition with iron and charcoal 
PR ESSE Cah CAG ie AE SID iate ada ies 
* Vide Mr. Kerr’s note in the 3d edition 
of his Translation of Lavoisicr’s Elements, p. 
420, 
had 
