But what is the most remarkable property?

The most remarkable property of potassium is its affinity for oxygen. It oxidizes rapidly in the air or oxygen gas; but if a piece be thrown upon water, it will decompose it rapidly, disengaging so much heat that the potassium takes fire and burns with a beautiful purple flame.

Has there been any experiment performed? The following is an instructive experiment: Take a piece of potassium, wrap it up in a small piece of paper, and introduce it quickly into a glass test tube, inverted in a small vessel of infusion of blue cabbage, the tube being filled with the same liquid. The metal will immediately rise to the top, and the moment the water reaches it through the paper, part of it will be decomposed, the oxygen combining with it and forming potassa, which changes the blue of the infusion to a green; while an equivalent portion of hydrogen gas is found in the tube, and may be inflamed by a lighted taper. But, perhaps, the most striking illustration of the deoxidizing power of potassium is exhibited by its action on carbonic

acid

gas: it takes fire, and by uniting with its oxygen forms potassa, while the liberated carbon is deposited in the form of charcoal

-BECK.

Does potassium inflame in chlorine gas? Potassium inflames spontaneously in chlorine gas, and burns with great brilliancy, forming chloride of potassium.

Has potassium a strong affinity for chlorine?

Potassium has a stronger affinity for chlorine than for oxygen, as its oxides are decomposed by chlorine gas.

How is the potash of commerce obtained? The potash of commerce is chiefly obtained by evaporating the ley of wood or vegetable ashes.

What forms the basis of most soaps?
Potassa forms the basis of most soaps.

SODIUM.

By whom was sodium discovered? Sodium was discovered by Sir H. Davy, in the year 1807.

What are some of the properties of sodium?

Sodium is a solid, at ordinary temperatures; has the lustre and general appearance of silver. It possesses the property of welding; fuses at 200°, and rises in vapor at a full red heat. When exposed to the air, it soon tarnishes, though less rapidly than potassium.

What are some of the uses to which sodium is applied?

Sodium is employed in the manufacture of hard soaps, and for culinary and medical

purposes.

How is the peroxide of sodium obtained? The peroxide of sodium is obtained by heating sodium to a redness, in an excess pure oxygen. It has an orange color, but no acid or alkaline properties.

of

What is said of the hydrate of soda? "Soda (or rather the hydrate of soda), is distinguished from other alkaline bases by the following characters: 1st, It yields with sulphuric acid, a salt, which, by its taste and form, is easily recognized as Glauber's salt, or sulphate of soda. 2d, All its salts are soluble in water, and are not precipitated by any reagent. 3d, On exposing its salts, by means of platinum wire, to the blowpipe flame, they communicate to it a rich yellow."-TURNER.

What is the chloride of sodium?

The chloride of sodium is commonly known in all countries as common salt; it is found in nature in rock salt, and in salt springs. More than 2,000,000 bushels are annually manufactured in the town of Salina, New York, alone.

What are some of the uses of chloride of

sodium?

It is used for bleaching, and removing the odors which arise from drains, sewers, or all kind of animal matter in a state of putrefaction. It is employed in surgical practice, for destroying the fetor of malignant ulcers.

LITHIUM.

Is lithium a metal?

Lithium is a white-colored metal, like

sodium.

By whom was it discovered?

Lithium was first obtained from lithia by Sir H. Davy, by means of galvanism; but it oxidized so rapidly, that he was unable to examine its properties.

How is lithia distinguished from potassa and soda?

Lithia is distinguished from potassa and soda, by its power of saturating a greater quantity of any acid. The chloride of lithium dissolves in alcohol, and the solution burns with a red flame. "The salts of lithia, when heated on platinum wire before the blowpipe, tinge the flame of a red color."TURNER.

LECTURE XLII.

FIRST CLASS OF METALS.

Order 2-Metals which, with oxygen, form alkaline

earths.

BARIUM, STRONTIUM, CALCIUM AND MAGNESIUM,
By whom was barium discovered?
Barium was first obtained by Sir H. Davy.
What are some of the properties of
barium?

Barium is of an iron gray color, with little lustre. It attracts oxygen from the atmosphere and from water, and crumbles into a white powder, which is the protoxide

of barium.

How may the peroxide of barium be ob

tained?

The peroxide of barium may be obtained by heating baryta in oxygen gas.

What is the process by which barium is

obtained?

The process consists in forming carbonate of baryta into a paste with water, and placing a globule of mercury into a little hollow made in its surface. The paste was upon a platinum tray which communi

laid