CHEMISTRY. 



Olefiut 

 i% 



Carbonic 

 oxide. 



Hence it* constituent* are carbon and hydro- 

 The following are nearly the proportions : 

 28 hydrogen 

 72 oxygen 



100 



The ga* obtained from pit-coal by distillation, con- 

 sists chiefly of thi* gas. 



Carbureted hydrogen gas bums with a yellow 

 flame, and give* out a great deal of light. 



2. When four part* of sulphuric acid, and one 

 pirt of alcohol, are heated in a retort, a gas comes 

 over called olefianl gat, or super- carbureted hydrogen. 

 It i* invisible ; has a disagreeable smell ; its specific 

 gravity is 0.9745. It burn* with a dense white flame, 

 and great splendour, and require* thrice it* bulk of 

 oxygen for complete combustion. The products are 

 water and twice it* bulk of carbonic acid. Hence it 

 has been concluded, that thi* gas is composed of 



85 carbon 

 15 hydrogen 



100 



When thi* gas i* mixed with chlorine over water, 

 the bulk of the mixture diminishes rapidly ; and an 

 opal coloured substance, like oil, swims open the 

 surface of the liquid. This substance seems to be a 

 compound of the two gases. It dissolves in water, 

 alcohol, and ether, and gives these liquids a hot and 

 aromatic taste. It dissolves likewise in nitric acid 

 without effervescence ; but in sulphuric acid it effer- 

 vesces, and chlorine is emitted. 



3. Carkonic oxide. When a mixture of equal 

 parts of iron filings and dry chalk is heated to redness 

 in an iron retort, a gas comes over, partly carbonic 

 acid and partly carbonic oxide. The former is wash- 

 ed away by means of lime water. 



Carbonic oxide gas is invisible ; its specific gravity 

 is 0.956. It burns with a deep blue flame, and 

 gives out but little light. For complete combustion, 

 100 measures of it require 40 of oxygen gas. The 

 product is 92 measures of carbonic acid. As the 

 carbonic acid produced is almost equal to the weight 

 of the carbonic oxide and oxygen consumed, it is 

 presumed that there is no other product. Hence 

 carbonic oxide is considered as a compound of car- 

 bon and oxygen in the following proportions : 



39 carbon 



61 oxygen 



100 



When equal bulks of this gas and chlorine gas are 

 exposed to a strong light over mercury, they com- 

 biue and form a gas jut half the bulk of the consti- 

 tuent*. It possesses acid properties. Water decom- 

 poses it ; and muriatic acid and carbonic acid are ob- 

 tained. This curioua gas was discovered by Mr John 

 Davy. Its specific gravity is 3'.669 ; and 100 cubic 

 inches of it weigh, under the mean pressure and tem- 

 perature, 111.91 grains. It combines with four 

 times its bulk of ammoniacal gas, and forms a neu- 

 tral salt. Alcohol absorbs about 12 time* its bulk 

 of this gas without decomposing it. Mr John Davy 

 ha* given this remarkable compound the name of 



. of 

 Chemntrjr. 



How pro- 

 cur <'- 



j t , proper- 

 tie*. 



johotgen gas, b*caue it it formed by the action of 

 liifht or its two constituents. 



SECT. III. Of Pliotj.honu. 



Phosphorus may be obtained by pouring acetate pliopho- 

 of lead into urine, mixing the whirr powder which ru^. 

 precipitates with charcoal, and distilling it in an earth- 

 en retort by means of a violent heat. The beak of 

 the retort ought be plunged under water. The phus- 

 phorus drops into the water like melted wax. It is 

 usually obtained from burnt bone*. 



It wa discovered in 1669, by Brandt, a chemist 

 of Hamburgh ; afterwards by Kunkel ; and last of 

 all by Boyle, who taught his operator, Godfrey 

 Hankwitz, to make it ; and he for several years was 

 the only person that could make it. 



Phosphorus, when pure, is semitransparent and 

 yellowish, but when kept in water it becomes white 

 and opake, and has some resemblance to white wax. 

 It is soft, and may be easily cut with a knife. It ii 

 insoluble in water. Its specific gravity is 1.770. 



It melts at the temperature of99. It cannot ea- 

 sily be melted in the open air without taking fire. If 

 air be excluded, it evaporates at 219, and boils at 

 554. 



When exposed to the air, it emits a white smoke 

 with the smell of -garlic, and is luminous in the dark. 

 This smoke is more abundant the higher the temper- 

 ature, and is occasioned by the gradual combustion 

 of the phosphorus. In oxygen gas it is not luminous 

 unless the temperature be as high as 80. Hence 

 we learn, that it burns at a lower temperature in com- 

 mon air than in oxygen gas. This slow combustion 

 in the open air, renders it necessary to keep phospho- 

 rus in phials filled with water and well corked. 



When heated to 148, it takes fire and burns with 

 a vivid white flame, and emitting a vast quantity of 

 smoke. It leaves (if pure) no residuum, but the 

 white smoke when collected is an ncitl, and is called 

 phosphoric acid. If the combustion be conducted 

 jn a jar filled with oxygen gas, the oxygen will be 

 found to diminish so much, that every 100 parts of 

 phosphorus occasion the disappearing of 1 14 parts of 

 oxygen. The acid formed weighs as much as the 

 phosphorus and the oxygen which have disappeared. 

 Hence it is considered as a compound of these two, 

 in the proportion of 100 parts of phosphorus to 114 

 of oxygen. 



Phosphorus is supposed capable of combining with 

 a small portion of oxygen, and of forming a com- 

 pound called oxide of phosphorus. It may be formed 

 by putting a bit of phosphorus in a long glass tube, 

 and exposing it to the heat of boiling water. It tub- 

 limcs and lines the tube in fine white flakes. Thi* 

 substance is very combustible, and often takes fire 

 of its own accord when exposed to the air. 



When introduced into chlorine, phosphorus burns 

 with a clear bluish white flame, and is converted into 

 a solid white matter, which seems to consist of the 

 two substances united. When this compound is pla- 

 ced in contact with water, it is converted into phos- 

 phoric acid and muriatic acid. 



When phosphorus is melted by means of a burning 



phospho. 

 ric acid. 



Oxide of 

 ph"pl>- 

 ri 



