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1. Alumino, argil, or pure clay, is infusible by the greatest beat; but beat wakes it so hard as to scratch glass. It readily absorbs water, and also grease; and bonce its 1180, as foller's earth, in scouring cloths, &c.

2. Linse, or calcareous earth, is obtained by applying bent to chalk, marble, limestone, &c. hy which carbonic acid gas and water are expelled, and the line left as a product.

When used as n coment in building, water is used to make it plastics and, with the addition of asher, or snnd, 10 supply carbonic acid, acquired its original hardness.

Lima is also used in tanning: in making sugar and soape and it forms 80 parts, combined with 20 of phos. phoric acid, in 100 paris of animal bones.

Lime is antiseptic, a few drachms, stirred in a cask of impure water, will render the whole perfectly sweet.

3. Magnesia, is a soft, white carth, generally found ia combination with sulphur. United with sulphuric acid, it forms that sulphate called Epsom-ulis.

4. Silex, or fint, is the principal ingredient of stones, crystals, sand, &c., and cannot be melted by itself in any heat; but in contact with alkulies, nie soda or pol-ash, it forms that useful production called glass.

622. The immense stony, masses of wliich the globe is composed, are found in the carth lying in strata one above another; a rock of one kind covering another species of rock; this a third. and so on.

The arrangement is not arbitrary; but cach species occupies ils regular place, from the deepesi part yet explored, to the surface.

Obs.- Rocks are divided into five classes or formations called primitive, transition, stratificil, alluvial, and valeuruc

1. The primitive formations of rocks are the lowest and are supposed to have been chemical precipitations, formed in the chaotic state of the earth; breause they have no petrifnctions or trace of organized beiogs. They are chiedy composed of silicious ad argillaccous earth, un granite, slate, &c.

2. Transilion-rocks are supposed to have been formeil during the transition of the earth into a habitable alates

and alder from primitive, in the variety of their colours, aud in containing the remains of marine animals.

3. Stratified rocks are disposed in borivontal strath they contain the remains of animals and vegetables, que consequently were formed after the creation of animals. gud vegetables.

. Allurial formations consist of the constituent parts of previous rocks, separated by water, air, &c. and deposited in beds. These are compounded of sand, gravel, loam, clay, turf, me, and contain Manta Boots, moss, boues, &c. : likewise petritied wood, and skeletons of quadrupeds :- the remains of destroyed worlds. 15, Volcanic formations are minerals thrown out of the crater of a volcano, consisting of pumice-stones, tava, and basalts.',

$23. All Acids consist of certain bases combined with oxygen, wliich is considered as the general cause of acidity.

Obs. 1.- Acids exciten spur taste on the tongue; change vegetable blue colours into red; and are either solid, liquid, or gaseous Acids unite with water in every proportion, and some of them have such an affinity for it, is never to quit their duid state. They also combine with the alka. lies, earths, and metallic oxydes, forming salts.

9.-Salts many be formed by are but many exist in mature, ready formed. Sales possess double names, for example, the Nitric Acid coinbined with Potass forms what is called Nitrate of Potass.

5:24. There is also another property in naiure, called the alkaline, which is distinguished from the acid by its burning and urinous taste; and it has the distinct property of converting vegetable blues into greens.'

The two alkalies are potass and soda; and there is also a rolatile alkali called ammonia,

Obs. 1.-Alkalies and acids have the property, when comhived, of neutralizing encla others and hence neid, when combined with alkalios, form what are called Neutral Salts.

.--Alkalies, mixed with fals, make seap; and, whea farlted, uiti sile.r, glass.

S. pluss is chietis obtained hy burning vegetables, as kali, &c., and hence called pet-akes; but CPA other altisli, is obtained froua siit-salt, from natru bonis and even froin wines, annonia is obtained from milsuhutances, viz, boves and urine; and also in the distillation of coals for gas.

525. The several Acids witherto discarered are 44 in number. 11 Vineral, & detaile. 13 Pepetroke Agadir tal Sulphureus, Arsenious, Acetic, Phosphurate, Sulphuric, Anenic,

Malic, Phosphoric Nitrous, Tuugstie, Oxalic, Bombie, Nitrie,

Molybdic, Citric, Sebacie, Muriatic, Chromic, Tartaric, Locric, Oxv-Muriatic, Columbie, Tartareous, Lactic, Carbonic Molybdenous, Benzoic, Serecho-Lactic, Fluoric,

Camphoric, Prusic, Koracic,

Gallic, Aarniotic, tellithic,

Succinic, lithic, Hyper-Oxy-Muriatic. Suberic, Rosacie.

Vucous,

Moroxylic. 526. The principal Acids obtained by the mixture of caygen with other substances are

Orygen and sulphur, called suiphuric ach. or oil ot' vitriol.

Oxygen and nitregen, called xilrec acid which dissolves silver, and thence the art ei plating with silver.

Oxygen and Chlorine called uuriatic aciel, or acid of sea salt;--this acid, united to soda, us called muriąt of soda, which is the commea si of the table.

Obs. I.-Orygen, and Fluorina, obtained from the shire-spar, is called fuoric acid, and enaburinn etching on glass. Bro-auriatic acid, or aqua erona dissolves gold and platina.

8. Adida may combine with two or moro subitanceo, and the product is called a triple compound, Thas sulphurie acid, combined with alumine and potass, forms alum, or sulphat of alumine and potass, and Tartar emetic to the tartrate of the metal antimony, and potass,

527. SALTS formed from acids comLined with alkalies, earths, or oxydes, amount to many thousands.

Those of which sulphuric acid, or oil of vin triol, forms a part, are Sulphate of Soda,

Sulphate of Magnesia,
Potass,

Alumine,
Barytes,

Iron,
Lime,

Copper, de,
Those of which Nitric Acid are formed, are
Nitrate of Potash,
Silver,

Nitrate of Mercury, |

Copper, &c.
Muriatie Acid is a component part of
Muriate of Soda,

Muriate of Mercury,
Ammonia,

Copper,
Barytes,

Iron,
Lime,

Lend,
Silver,

Cobalt, &e,
Oxymuriatic

Acid forins a part of

Seda, Nitric and Muriatic Acid combined, form Nitro-Muriates. These are Nitro Muriate of Gold, Nitro murlate of Cobalt.

Tin, 1528. Metala are seldom found in the earth in a pure state, but generally in combination with oxygen, earths, sulphur, and acids, In these states of combination, they are called ores ; and are generally found in mines. (See article Metallurgy, p. 16.)

Obs. I.-Metals are fusible by heat, and when suffered te cool gradually, they cryoluline.' H they are eu

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tinued in fusion, they absorb * certnin poriton of oxveen, June their brillianey, and become welahir oxudes, Worter also oxidates metals. Its hydrogen bring dincopaned, the oxygen unites with the metal Metals are soluble ia acids, and may be precipirated froin then by wikalies. When perfectly fused, they are mirrible with each other, forming alloys, and with other substances, is stilyhur, phosphorts, and charcoal.

2.- In the reduction of metal from their styles, the addition of a combustible #ubstance is necewart'; chai. coal for instance, Iron und platina grow soft before they fuse, lience their useful property of being woulded. Metals are excellent contacture of electricity. All me. talenre combustible lone will burn before they are kot enmigh to mell.

9. The property whiclo metals pogue of bring combined with each other, renders tremi very well. Copper and wind forw brass, lead and tin, pewier

3:20. The Metals at present known, are 28 in number. 10 Mallable.

B Fosible. 13 Fased with Dimculty, Platina, Bismuth, (Shale, Gold, Antimony, Manganese, Nilver, Tellurium, Tungocelt Mercury, Arsenic. Molybdenum, Copper,

Uniune,

Tinium,
Tin,
Chromiun. Columbium, or

'Tunenlinin, Nickel,

Oerinin,
Ziuc,

Cemimp, ! !
Iridinen,
Pullarium,

Rhodion. 630. All Mineral Waters are formed by the solution, or mixture in them, of oxygen or Nitrogen gases, or of veids, alkalice, and neutra!

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