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Magnesium oxide

One of these he says is found in magnesia, is white in colour, does not attract iron and is like pumice stone.

On the 12th of July 1444 a ten years' peace was signed with Hungary, whereby Walachia was placed under the suzerainty of that country; and, wearied by constant warfare and afflicted by the death of his eldest son, Prince Ala-ud-din, Murad abdicated in favour of his son Mahommed, then only fourteen years of age, and retired to Magnesia (1444).

It is also obtained by passing chlorine into a suspension of lead oxide or carbonate, or of magnesia and lead sulphate, in water; or by treating the sesquioxide or red oxide with nitric acid.

It is to be distinguished from an archaic figure still visible, carved in the northern side of the mountain near Magnesia, to which tradition has given the name of Niobe, but which is really intended for Cybele.

Ore endowed with this curious property was well known to the ancient Greeks and Romans, who, because it occurred plentifully in the district of Magnesia near the Aegean coast, gave it the name of magnes, or the Magnesian stone.

In this neighbourhood fragments and lumps of glass are still constantly being dug up, and analysis proves that the glass contains a considerable proportion of magnesia.

An analysis of the glass of a Cairene mosque lamp shows that it is a soda-lime glass and contains as much as 4% of magnesia.

This large proportion of magnesia undoubtedly supplied the stability required to withstand the process of enamelling.

Loew, who prepared in 1885 a sweet, unfermentable syrup, which he named formose, C6H120e and, later, by using magnesia instead of lime, he obtained the fermentable methose.

In the ordinary chemical analyses of the soil determinations are made of the nitrogen and various carbonates present as well as of the amount of phosphoric acid, potash, soda, magnesia and other components soluble in strong hydrochloric acid.

When prolonged heating is required at very high temperatures it is found necessary to line the furnace-cavity with alternate layers of magnesia and carbon, taking care that the lamina next to the lime is of magnesia; if this were not done the lime in contact with the carbon crucible would form calcium carbide and would slag down, but magnesia does not yield a carbide in this way.

Taking magnesia alba, which he distinguished from limestone with which it had previously been confused, he showed that on being heated it lost weight owing to the escape of this fixed air (named carbonic acid by Lavoisier in 1781), and that the weight was regained when the calcined product was made to reabsorb the fixed air with which it had parted.

This battle made Philip tagus of Thessaly, and he claimed as his own Magnesia, with the important harbour of Pagasae.

Filtration in the chemical laboratory is commonly effected by the aid of a special kind of unsized paper, which in the more expensive varieties is practically pure cellulose, impurities like feric oxide, alumina, lime, magnesia and silica having been removed by treatment with hydrochloric and hydrofluoric acids.

According to tradition, reinforced by the similarity of names, it was founded by colonists from the Thessalian tribe of the Magnetes, with whom were associated, according to Strabo, some Cretan settlers (Magnesia retained a connexion with Crete, as inscriptions found there attest).

The railway runs right through the precinct, and much of Magnesia has gone into its bridges and embankments.

Magnesia continued under the kings of Pergamum to be one of the most flourishing cities in this part of Asia; it resisted Mithradates in 87 B.C., and was rewarded with civic freedom by Sulla; but it appears to have greatly declined under the Roman empire, and its name disappears from history, though on coins of the time of Gordian it still claimed to be the seventh city of Asia.

Haumann, Magnesia am Maeander (1904).

They may be extracted by exhausting the plant-tissues with a dilute acid, and precipitating the bases with potash, soda, lime or magnesia.

Euboea at the present time produces a large amount of grain, and its mineral wealth is also considerable, great quantities of magnesia and lignite being exported.

Valentin prepared magnesia alba from the mother liquors obtained in the manufacture of nitre.

It also burns when heated in a current of steam, which it decomposes with the liberation of hydrogen and the formation of magnesia.

Magnesium Oxide, magnesia, MgO, occurs native as the mineral periclase, and is formed when magnesium burns in air; it may also be prepared by the gentle ignition of the hydroxide or carbonate.

A strong solution of the chloride made into a thick paste with calcined magnesia sets in a few hours to a hard, stone-like mass, which contains an oxychloride of varying composition.

Magnesium oxychloride when heated to redness in a current of air evolves a mixture of hydrochloric acid and chlorine and leaves a residue of magnesia, a reaction which is employed in the Weldon-Pechiney and Mond processes for the manufacture of chlorine.

Magnesia alba, a white bulky precipitate obtained by adding sodium carbonate to Epsom salts,is a mixture of Mg(CO 3 H) (OH) 2H 2 O,Mg(CO 3 H) (OH) and Mg(OH) 2.

When heated in dry oxygen it becomes incandescent, forming magnesia.

Magnesium sulphide, MgS, may be obtained, mixed with some unaltered metal and some magnesia, as a hard brown mass by heating magnesia, in sulphur vapour.

There Antiochus the Great collected the army with which he met the Romans at Magnesia, and there two years later the treaty between Rome and the Seleucid realm was signed.

With this pile he decomposed sulphate of magnesia (first letter to Abbott, July 12, 1812).

The matter was carefully investigated, and it was found that the sulphate of magnesia in the sea-water has a decomposing action on Portland cements, especially those which contain a large proportion of lime or even of alumina.

The usual composition of this slag is iron oxide, i o to 16%; lime, 40 to 50%; magnesia, 5%; silica, 6 to 9%; phosphoric acid, 16 to 20%.

The lining of the converter is made of 90% of the mixture of lime and magnesia which results from calcining dolomite, (Ca,Mg)CO i, at a very high temperature, and 10% of coal tar freed from its water by heating.

While the proportion of common salt to sulphate of magnesia is as r r to r in the water of the Black Sea and as 2 to 1 in the Caspian water generally, it is as 12.8 to 5.03 in the Kara-boghaz.

Antioch in Persis, of course, sends athletes to the great games of Greece, but in this decree it determines to take part in the new festival being started in honour of Artemis at Magnesia.

Many of the Egyptian rocks in the desert areas and at the cataracts are coated with a highly polished film, of almost microscopic thinness, consisting chiefly of oxides of iron and manganese with salts of magnesia and lime.

The remaining silicates and aluminates present, and ferric oxide and magnesia, if existing in the moderate quantities which are usual in Portland cement of good quality, are of minor importance and may be regarded as little more than impurities.

Magnesia, if present in Portland cement in quantity not exceeding 5%, appears to be inert, but there is evidence that in larger proportion, e.g.

In so-called natural cement which is comparatively lightly burnt, the magnesia appears to be inert, and as much as 20 to 30% may be present.

They are usually made from a silicious limestone containing magnesia, and are comparatively lightly burned.

Wahl [German patent 70773 (1893)] prepare a 97% manganese from pyrolusite by heating it with 30% sulphuric acid, the product being then converted into manganous oxide by heating in a current of reducing gas at a dull red heat, cooled in a reducing atmosphere, and finally reduced by heating with granulated aluminium in a magnesia crucible with lime and fluorspar as a flux.

The metals, which by combination with oxygen became oxides, were antimony, silver, arsenic, bismuth, cobalt, copper, tin, iron, manganese, mercury, molybdenum, nickel, gold, platinum, lead, tungsten and zinc; and the "simple earthy salifiable substances" were lime, baryta, magnesia, alumina and silica.

His army was practically destroyed at Magnesia, and he was forced to accept the terms of peace, which the Romans had offered and he had refused before the battle.

For the manufacture of bleaching-powder, limestone of high degree of purity (especially free from magnesia and iron) is carefully burned so as to drive out nearly all the carbon dioxide without overheating the lime.

In recent years it has been found in considerable quantities in New Caledonia in the form of a hydrated silicate of nickel and magnesia approximating to the constitution (NiO, MgO) SiO 2 .

The defeat of Antiochus the Great at Magnesia, 190 B.C., placed Asia Minor at the mercy of Rome; but it was not until 133 that the first Roman province, Asia, was formed to include only western Anatolia, without Bithynia.

His method consisted in using magnesia instead of lime for the recovery of the ammonia (which occurs in the form of ammonium chloride in the ammonia-soda process), and then by evaporating the magnesium chloride solution and heating the residue in steam, to condense the acid vapours and so obtain hydrochloric acid.

These cylinders are filled with pills, made of a mixture of magnesia, potassium chloride and fireclay, the object of the potassium chloride being to prevent any formation of hydrochloric acid, which might occur if the magnesia was not perfectly dry.

In these cases lime-water, alkalis and magnesia should be used as antidotes, and opium may be required.

Even in cases of very acute intestinal diseases similar treatment is now pursued, and instead of treating dysentery simply by sedatives or astringents, an eliminative treatment by means of sulphate of magnesia is largely employed.