68 L/TERARY AND SCIENTIFIC. 



liquids, and liquids and gaseous bodies often become solid. Gypsum, or plaster of 

 Paris, a perfectly tasteless substance, is composed of 40 parts of sulphuric acid, 

 and 28 parts of quick lime, both highly corrosive bodies. Common salt is composed 

 of 36 parts of chlorine, a very suiFocating gas, and 24 parts of sodium; the metallic 

 base of soda. The salt called salammoniac, is composed of two gases, viz., the 

 muriatic acid gas and ammoniacal gas. 



Mr. W. here illustrated the above remarks by numerous interesting cxperi- 

 nients; among which were the following : — 



1 . On mixing tog^ether sulphuric acid, and a solution of pure potash, both corrosive 

 bodies, they formed a neutral solution of sulphate of potash, possessing a slightly saline 

 taste, but neither acid nor alkaline. 



2. On introducing ammoniacal gas and carbonic acid gas into a glass vessel, they com- 

 bined and formed a crystalline solid. Carbonate of ammonia. 



3. On mixing together solutions of muriate of lime and carbonate of potash, the two 

 liquids instantly became solid. 



4. On displaying about four ounces each of salammoniac, salt petre, and glauber's salt in 

 about a pint of water, and introducing a glass of water into the solution, the water in 

 the glass was speedily frozen, and a degree of cold produced as low as 20" below the 

 freezing point. 



5. On mixing sulphuric acid and water together, a temperature equal to that of boiling 

 water was instantly obtained, and spirits of wine, contained in a long glass, boiled in it. 



Mr. W. then adverted to the proportions in which bodies unite in the formation 

 of compounds. 



Bodies appear to unite together in three ways. First, unlimitedly in every 

 proportion, as when spirits of wine and water, or sulphuric acid and water, are 

 mixed together; a drop of sulphuric acid may be combined with a gallon of water, 

 or a gallon of water may be combined with a drop of sulphuric acid, and the two 

 substances will be found intimately united in every poition of the liquid. 



Secondly, in every proportion within a certain limit, as when salts are dissolved 

 in water ; thus 100 pounds of water will dissolve any quantity of salt not ex- 

 ceeding 40 pounds. These kinds of combinations, however, may be regarded 

 rather as mixtures than as chemical compounds ; these substances undergo no 

 particular change by their union, and they still possess the separate properties of 

 each of the components. 



The third kind of combination always takes place between bodies in limited 

 and definite proportions, the knowledge of which constitutes an exceedingly 

 interesting and useful branch of study. The compounds thus formed always 

 possess properties essentially different from their constituents. 



In this way some bodies unite only in one proportion, as hydrogen with chlorine, 

 forming muriatic acid ; no other compound of these two elements being known. 



Other bodies unite in two proportions, as hydrogen with oxygen, forming water, 

 and deutoxide of hydrogen ; others unite in three, four, five, and, even, six pro- 

 portions ; but whenever two substances form more than one compound, the other 

 compounds contain multiple proportions of one of the elements of the first com- 

 pound; for instance, there are two compounds of mercury and oxygen, and they 

 are thus constituted. 



1st. — 8 parts of Oxygen to 200 parts of Mercury. 

 2d.— 16 parts of Oxygen to 200 parts of Mercury. 



The first is called the protoxide, the second, the per-oxide, of mercury. Oxygen 

 combines with nitrogen in no less than five distinct proportions, thus:— 



1 . — Protoxide of Nitrogen, 8 Oxygen, 14 Nitrogen. 



2. — Deutoxide of Nitrogen, 16 Oxygen, 1 4 Nitrogen . 



3. — Hyponitrous Acid, 24 Oxygen, 14 Nitrogen . 



4. — Nitrous Acid, 32 Oxygen, 14 Nitrogen. 



5.— Nitric Acid, 40 Oxygen, 14 Nitrogen. 



It will be observed that each of the proportions of oxygen is a multiple of 8, while 

 the proportion of nitrogen remains 14 in all the compounds. These num- 

 bers are the relative weights of each substance. 



Occasionally, however, we meet with two compounds, the second of which con- 

 tains only one-half more of one of the elements, for instance, the two oxides of iron 

 and the three oxides of lead are thus formed : — 



Protoxide of Iron Iron 28, Oxygen 8 



Per-oxide of Iron, Iron 28, Oxygen 12 



Protoxide of Lead, Lead 104, Oxygen 8 



Deutoxide of Lead, Lead 104, Oxygen 1 2 



Per-oxide of Lead, Lead 104, Oxygenic 



