530 



NEW ENGLAND FARIVIER. 



Nov. 



cess of putrefaction, — hence its presence in 

 decomposing manures. As it Is highly volatile 

 and tends to fly off as it is formed, some sub- 

 stance should be frequently added for which 

 it has an affinity, as sulphuric acid diluted with 

 water, sulphate of lime, peat, muck or loam, 

 with which it will combine, and be retained in 

 the decaying mass. 



Carbon. — This abounds in the animal, veg- 

 etable and mineral kingdoms. It enters into 

 the composition of the bones and soft tissues 

 of animals. It constitutes the largest part of 

 the bulk of vegetables. If these are burned 

 with the partial exclusion of air, so that there 

 shall not be oxygen enough present to enable 

 them to burn rapidly, the volatile portions will 

 be driven off by the heat, and the charcoal or 

 carbon will remain. 



Charcoal when freed from earthy matter is 

 nearly pure carbon. Mineral coal is composed 

 largely of carbon — the remains of former veg- 

 etation. The diamond is pure carbon, and 

 may be burned without leaving any ash behind. 

 Carbon is found in the form of carbonic acid, 

 combined with lime, in marble, coral, shells, 

 &c., and abundantly in nature. Plumbago, or 

 as it is called, black lead, is crystalized black 

 carbon. Carbon shows clearly how one and 

 the same body may have different forms and 

 different properties. In charcoal soot, coke 

 and animal charcoal, it is black, and very com- 

 bustible. In plumbago it is black, with a crys- 

 talized structure, and nearly incombustible, tto 

 that crucibles are made of it, which bear the 

 strongest fire without burning. In the diamond 

 it is colorless, and crystalized in the form of a 

 double pryamid, and is almost incombustible. 



Coal is not decomposed at common temper- 

 atures, that is, it does not enter into chemical 

 union with the oxygen of the air and water. 

 But when it is heated to redness this readily 

 takes place. It then burns and disappears, 

 with the exception of a small quantity of ashes. 

 The heat developed by the burning is the re- 

 sult of the chemical union of the carbon with 

 the oxygen of the air. The gas generated is 

 called carboni(^ acid, and consists of one part 

 or atom of carbon and two atoms of oxygen. 

 Carbonic acid is always formed when burning 

 charcoal has a sufficient supply of air ; but 

 when there is a deficiency of air, carbonic ox- 

 ide gas is formed, which consists of one atom 

 of carbon, and one of oxygen. This gas is 

 what miners call coal gas, or choke-damp. 

 This is very destructive to life when inhaled. 

 What is called the fume of charcoal, is the 

 result of the slow combustion of ciharcoal, as 

 when it is smothered with ashes which obstruct 

 the access of air, or when the damper of a 

 stove is closed before the coal is burned out, 

 which prevents the draught of air and conse- 

 quent suj)ply of oxygen. 



Carbonic acid is formed wherever substances 

 are burning, with free access of air ; wherever 

 men and animals are breathing ; and wherever 

 decay and putrefaction are going on ; and 



thrown into the atmospheric ocean by which 

 the earth and all its products are constantly 

 bathed. From the atmosphere it is absorbed 

 by all growing vegetables, and thus its injuri- 

 ous accumulation is prevented, which occurs 

 only in exceptional instances, and a due equi- 

 librium is preserved. From its existing largely ■ 

 in nature in carbonate of lime and other alka- 

 lies, it was called by Dr. Black, fixed air. 

 Many springs are impregnated with this gas, 

 which gives their waters a sparkling appear- 

 ance and a fresh and pleasant taste. Immense 

 quantities of water are artificially prepared 

 under the name of soda wa er by impregnat- 

 ing them with carbonic acid gas. It is about 

 one-third heavier than atmospheric air, and 

 may be poured from one vessel to another like 

 water. If air contains more than fifteen per 

 cent, in bulk of this gas, it will not support 

 animal life or combustion. Lighted candles 

 will be extinguished in it. R. 



Concord, Mass., Sept. 28, 1867. 



For the New England Farmer, 

 CHEMISTRY. 



If I rightly remember, common salt was for- 

 merly called by chemists, muriate of soda ; and 

 was believed to be such a chemical combina- 

 tion as the name indicated. Subsequent ex- 

 periments, such as the combustion of the metal 

 sodium in chlorine gas, seemed to prove that 

 it had been wrongly named, and thenceforth 

 it was called, technically, chloride of sodium, 

 a name clearly Indicating Its true combination. 

 Not being well versed In recent chemistry, I 

 was not aware that the name had been again 

 changed, until I saw "Chemical Terms," No. 2, 

 in the FAKjrER of 21st of Sept. Inst. ; where 

 It Is called, "chloride of sodaf — thus making 

 it a hitherto unknown and anomalous combina- 

 tion of chlorine and the protoxide of sodium ; 

 — or else the writer or printer has so confound- 

 ed "chemical terms," as to put soda, the pro- 

 toxide of a metal for sodium, the metal pure 

 and simple. In either case It (common salt) 

 is not well chosen as an example of the com- 

 bination of an acid with a base ; for If we may 

 rely on modern chemistry, only three years old, 

 common salt, — unlike sulphate of soda, Glau- 

 ber's salts, — Is a haloid or binary salt, and a 

 chemical combination of the elementary gas, 

 chlorine, and the metal sodium, and is there- 

 fore called, technically, chloride of sodium. 

 In the common language of chemistry, chlorine 

 Is not an acid, neither is sodium such a base as 

 comes under the definition, "an alkali or oxide 

 of a metal." But a base, as a general chemi- 

 cal term is, "the principal element of a com- 

 pound, usually electro-positive in quality." 

 Webster. 



Filtration. — [The straining of a liquid 

 through unsized paper, felt, fulled cloth, or 

 other permeable substance, so as to separate 

 therefrom precipitates and other impurities, is 

 called a filtration ; therefore, filtration is the 



