CHEMISTRY. 



Element! 



of 

 Chemistry, 



How ob- 

 tained. 



Its proper 

 tki. 



Composi- 

 tion. 



be obtained by burning phosphorus, or by dissolving 

 phosphorus in nitric acid, and evaporating the liquid 

 to dryness. 



In this state it is solid, colourless, and transparent, 

 not unlike glass. It reddens vegetable blues, has no 

 smell, but has a very acid taste. When exposed to the 

 air, it attracts moisture, and gradually runs into an 

 oily-like fluid. Its specific gravity when in the state 

 of glass is 2.8516 ; when in the liquid state, 1.417. 



It is very soluble in water, and is said to be capa- 

 ble of crystallizing, but it is difficult to obtain it in 

 that state. 



Oxygen has no effect upon it. None of the sim- 

 ple combustibles are known to be capable of decom- 

 posing it, except charcoal. When strongly heated 

 with this substance, phosphorus is disengaged. The 

 simple incombustible* have no effect on it. 



It is capable of oxidizing and dissolving some of 

 the metals ; but its action on these bodies is by no 

 means strong. 



It combines with the salifiable bases, and forms a 

 class of salts called phosphates. 



According to the experiments of Rose, it is com- 

 posed of 46.5 phosphorus, 

 53.5 oxygen. 



100.0 



SECT. IV. Of Phosphorous Acid. 



Phospho- This acid was known earlier than the preceding, 

 roui acid. For a long time they were confounded. Lavoisier 

 was, perhaps, the first who accurately distinguished 

 How ob- them. It may be obtained by exposing phosphorus 

 tained. to tne O p en a j r . j t gradually absorbs oxygen, and 



runs into a liquid, which is the acid in question. 

 Iti proper- ' l '* a viscid colourless liquid, having a very acid 

 ties. taste, and emitting the smell of garlic, especially 



when heated. It combines with water in any pro- 

 portion. When evaporated to drynes* and heated, 

 it gives out phosphureted hydrogen gas, which burns 

 when it comes in contact with the air. This con- 

 tinues for a long time, and at last the acid is convert- 

 ed into the phosphoric. If nitric acid be poured 

 upon it, this change takei place much more easily 

 and speedily. 



The action of the simple combustibles, the incom- 

 bustibles, and the metals on thil acid, is similar to 

 their action en phosphoric acid. 



It combines with the different salifiable bases, and 

 forms a class of salts called phorphile*. 



Sulphuric acid, by the assistance of heat, converts 

 it into phosphoric acid. 



It has been ascertained that this acid contains less 

 oxygen than the phosphoric, but the actual proper, 

 tion has not been determined 



SECT. V. Of Carbonic Acid. 



Carbonic Thi* acid was discovered by Dr Black. It pro- 

 acid. perties were afterwards investigated by Mr Caven- 



dish and Dr Priestley, and its composition ascertained 

 by Mr Lavoisier. It was at first called Jixed air. 

 Mr Lavoisier, after ascertaining its base, gave it the 

 amc which it now bears. Every chemist almost of 



eminence, during the last 50 years, has added some- Element 

 thing to our knowledge of the properties of this re- of 

 markable substance. Chemistry.. 



It may be obtained by burning charcoal, or more Hmvob-^ 

 easily by pouring muriatic acid on chalk in a glass tained. 

 retort, and receiving the gas which is extricated in 

 glass jars over water. This gas is the acid in ques- 

 tion. 



It is invisible, and possesses the mechanical pro- tts proper- 

 perties of air. No combustible will burn in it. It ties, 

 is unfit for respiration. It affects the nostrils with a 

 kind of pungent sensation, but when diluted with 

 air, it has no smell whatever. Its specific gravity 

 is 1.500, that of air being 1.000. It reddens very 

 delicate vegetable blues. 



Atmospheric air contains about t$ es of its bulk of 

 this gas. 



It is not altered by passing it through a red hot 

 tube ; but when electric sparks are passed through it 

 for a long time, its bulk increases, and a portion of 

 carbonic oxide is evolved. 



Water absorbs it when placed in contact with it. 

 The rapidity of the absorption is much increased by 

 agitation. Water absorbs its own bulk of this gas 

 at the temperature of 41. The water acquires a 

 sour taste, a sparkling appearance, and the property 

 of reddening vegetable blues. When heated or fro- 

 zen, the gas is extricated. It makes its escape also 

 if the liquid be left exposed to the open air. 



Carbonic acid is not acted upon by oxygen, nor, 

 as far as is known, is it altered by any of the simple 

 combustibles, incombustibles, or metals. But several 

 of these bodies, as charcoal, phosphorus and different 

 metals, have the property of decomposing it at a 

 red heat, when it is in combination with lime, baty- 

 tes, or strontian. In these cases a quantity of carbo- 

 nic oxide is usually evolved. 



It combines with the salifiable bases, and forms a 

 class of salts called carbonate*. 



From the most exact experiments hitherto made, Composi- 

 we may consider this acid as composed very nearly tion. 

 of 



28 carbon. 

 72 oxygen. 



100 



SECT. VI. QfBoracic Acid. 



This acid is obtained from the salt called boras, Boracic 

 brought to Europe from the East, where it is found acid, 

 chiefly at the bottom of some lakes in Thibet and 

 China. It was first extracted from borax by Hom- 

 berg, and its nature was ascertained by Baron. To How ob- 

 obtain it, dissolve borax in hot water, and add sul- tained. 

 phuric acid till the liquid assumes a sensibly acid 

 taste. As the liquid cools, it deposites white crys- 

 talline scale*, which are boracic acid. 



Thus obtained, it has the form of thin hexagonal Its proper- 

 scales of a silvery whiteness. Its taste is sourish and ties, 

 bitterish. It has no smell. It reddens vegetable 

 blues. Its specific gravity, while in scales, is 1.479, 

 when melted 1.803. 



It is not altered by light nor heat. In a red heat 

 it melts into a transparent colourless glass, which be- 



