CHEMISTRY. 



13 





eiementi glass in hydrogen ga, a portion of it is dissolved, 



f and a new gas formed, first disrov<-r. d by Gemgembre, 



Chemistry. an( j Ci jj e< j phowhureted hydrogen gas. It has a 



PI, > ^k , fetid odour like the snv.'ll of putrid fish. It burns 



i * L 



reted hy- spontaneously, when it comes into contact with com- 

 drogen. mon air or oxygen gas. Water dissolves a small por- 

 tion of this gas, and acquires a bitter taste and un- 

 pleasant odour. The phosphorus gradually precipi- 

 tates, and the hydrogen at the same time separates 

 from the water. When kept in a glass jar, it soon 

 loses its property of burning spontaneously. 



From the experiments of Mr Davy, we learn, that 

 when hydrogen gas is converted into phosphureted 

 hydrogen, its bulk does not alter ; and from the ex- 

 periments of Mr Dalton, it follows, that the weight 

 of 100 cubic inches of it under the common pressure, 

 and at the temperature of 60, is 26 grains. From 

 these data, it is easy to establish its composition. Its 

 constituents are obviously, 



phosphorus 91.23 

 hydrogen 8.77 



100.00 



Phosphorus combines with charcoal, and forms a 

 compound of an orange red colour, called phosphuret 

 of carbon. Common phosphorus contains a portion 

 of this compound, which remains behind when the 

 phosphorus is burnt. It is a light flocky powder, 

 without taste or smell. When heated sufficiently, it 

 burns, and the charcoal remains behind. 



The compounds which phosphorus forms with 

 the other bodies, are distinguished by the name of 

 phosphureU. 



Phosphorus is very poisonous when used internal- 

 ly. It has been recommended as a medicine, and said 

 to be very efficacious in restoring the force of young 

 persons exhausted by sensual indulgence. 



Sulphur. 



lu proper- 

 tin. 



Sulphuric 



SECT. IV. Of Sulphur. 



Sulphur, distinguished also by the name of brim- 

 ttone, has been known since the earliest ages. 



1* ' a nar d brittle substance, of a greenish yellow 

 colour, without any smell, and with very little taste. 

 It is a nonconductor of electricity, and becomes elec- 

 tric negatively by friction. Its specific gravity is 

 1.990. ft i not altered by exposure to the air, nor 

 is it soluble in water. 



When heated to 170 it rises up in the form of a 

 fine powder, which may be easily collected, and is 

 cMrdJlorvers of sulphur. It is then said to be vola- 

 tilizfd or sublimed. It is obvious, from this property, 

 that sulphur is a volatile substance. 



When heated to about 218 it melts, becomes 

 transparent, and looks like a brown coloured oil. At 

 560' it boils and the vapour kindles as it exhales, 

 and burns with a blue flame, and an extremely disa- 

 greeable smell. If it be set on fire, and plunged into 

 a jar filled with oxygen gas, it burns with a strong 

 violet flame. In both cases (provided the quantity 

 of air or oxygen be sufficient) it burns away com- 

 pletely without leaving any residue. But if the fumes 

 be collected, they are found to be an acid, which is 

 known by the name of sulphuric acid. A portion of 

 the oxygen disappears ; and, from the experiments 



of Lavoisier, it follows, that the sulphuric acid form- Elements 

 ed is exactly equal in weight to the sulphur and the ' 

 oxygen which have disappeared during the combus- ^ emli ^>- 

 tion. Hence it is concluded, that this acid is com- 

 posed of these two substances united together. 



Many experiments have been made to ascertain the 

 composition of sulphuric acid exactly. The follow- 

 ing is the result which appears most accurate. It 

 was obtained by Berzelius. 



100 sulphur 

 150 oxygen 



250 



But sulphur does not always combine with so great Sulphurou* 

 a portion of oxygen. It usually burns with a blue acid, 

 flame, and the suffocating vapours which it emits may 

 be collected in glass cylinders filled with mercury, 

 and standing in a trough containing mercury. They 

 constitute a gas called sulphurous acid. It contains 

 less oxygen than sulphuric acid, being compounded 

 of 



100 sulphur 



100 oxygen 



200 



When sulphur is kept melted in an open crucible, 

 it becomes gradually thick and viscid. If it be 

 now poured into water, it assumes a purple colour, 

 and remains for some days soft ; but it gradually be- 

 comes brittle, and of a light violet colour. Its tex- 

 ture is fibrous, and its specific gravity 2.325. In 

 this state it has been called oxide of sulphur, from an 

 opinion that it has combined with a little oxygen, and 

 that this addition has altered its properties. But this 

 opinion has not been proved experimentally. 



When sulphur is dissolved in any liquid, as in a so- 

 lution of potash, and then precipitated by an acid, it 

 is always in the state of a white powder, known by the 

 name of lac snlphuris. This powder consists of sul- Lactuf- 

 phur combined with a little water. When the water phuris. 

 is driven off by heat, the white colour of the oulphur 

 disappears, and its natural yellow colour returns. 



When a current of chlorine is made to pass through 

 a quantity of flowers of sulphur, or when sulphur is 

 heated in chlorine, it gradually disappears, and a beau- 

 tiful red liquid appears in its place. Its specific gra- 

 vity is 1.623. It smokes very strongly, has a strong 

 smell, and is very volatile. It dissolves pho.-pnoriu 

 readily. When mixed with water, it is decomposed, 

 and a quantity of sulphur separates. This substance 

 is obviously a compound of sulphur and chlon.ie. 

 Water decomposes it ; and, in that case, sulphuric and 

 muriatic acids are formed. 



Sulphur combines readily with hydrogen gas, and Sulplmre- 

 forms a gas known by the name of sulphureted hy- < ed hydro- 

 drogen, which was first described by Scnecle. S tn ' 



It may be formed by mixing together potash and 

 sulphur, and boiling them together in a glass flask. 

 When sulphuric acid is poured into the yellowish, 

 coloured liquid that is formed, an effervescence takes 

 place, and the gas may be collected in proper vessels. 

 It is obtained pure by digesting sulphuret of anti- 

 mony in muriatic acid. 



Sulphureted hydrogen gas is colourless, and pos- 

 sesses the mechanical properties of common air. It 



