797 



CHEMICAL NOMENCLATURE. 



CHEMISTRY. 



798 



with a sesquioxide as well as with a protoxide of the metal, as is the 

 case with iron, the salts "are called respectively sulphate of protoxide, 

 and sulphate of peroxide of iron ; or, more briefly, protosulphate and 

 persulphate of iron. These two oxides of iron are termed respectively 

 ferrous and ferric oxide, and these salts it has been proposed to term 

 ferrous and ferric sulphate. This mode of nomenclature has much that 

 is advantageous, and has been extended to several other cases ; thus, 

 the terms mercurous nitrate, and mercuric nitrate, express respectively 

 the nitrate of protoxide of mercury, and the nitrate of peroxide of 

 mercury. 



Where an acid combines with a base in more proportions than one, 

 the principles heretofore described obtain. \Ve have thus sulphate and 

 bisulpltate of potash, to express the combination of 1 and 2 equivalents 

 of sulphuric acid respectively with the base potash ; Oxalate, binoxalate, 

 and quadroxalate of potash, to express respectively the combinations of 

 1, 2, and 4 equivalents of oxalic acid with 1 equivalent of potash. 

 Sesqwcarbonate of soda signifies a combination of 1| equivalents of 

 carbonic acid with 1 equivalent of soda. 



Salts containing more base than exists in the neutral salt are termed 

 batic salts or subsalts. We have acetate of lead, and subacetate of lead ; 

 sulphate of iron, and tribaxic sulphate of iron : the latter expressing a 

 proportion of base three times that which exists in the neutral salt. 



Combinations of water with acids or with bases are termed hydrates ; 

 thus, hydrate of potass (KOHO), hydrated boracic acid (B0 3 3HO). 



Double salts are expressed by the names of the salts of which they 

 consist : the name of the common acid not being repeated. Sulphate 

 of i-i'pper and potash expresses the combination of sulphate of copper 

 with sulphate of potash ; chloride of platinum and potassium (KC1, 

 PtCl,) expresses the combination of chloride of platinum with chloride 

 of potassium. Some chemists regard the chloride of platinum as 

 playing the part of an acid, and the above compound is frequently 

 termed platinochloride of potassium. 



In the present state of organic chemistry, in which new substances 

 and new processes are being discovered daily, it would be impossible to 

 propose any system of nomenclature which could at all claim to be 

 permanent. The difficulties are further enhanced by the great differ- 

 ence of opinion which prevails among chemists as to the constitution 

 of organic compounds. Bodies which have been studied by different 

 chemists, and which admit of being regarded from different points of 

 view, frequently possess several names. Thus, chloroform, C 2 HCl a , 

 may receive different names according as we view it, as C 2 H'"C1 3 , the 



H 1 



Cl 

 chloride of the tribasic radical formyl, C 2 H'", or as being C 2 ^ > 



ClJ 



marsh gas (C,H t ), in which 3 equivalents of hydrogen are replaced by 

 3 equivalents of chlorine. The nomenclature of organic compounds 

 hence bears, to a certain extent, the impress of the state of transition ; 

 and, under these circumstances, it would be impossible iu this brief 

 apace to do more than briefly indicate, in the most general manner, 

 the application of the principles of nomenclature in certain special 

 important families. 



Certain groups of organic compounds, generally consisting of carbon 

 and hydrogen, have the property of entering into combination with 

 elementary bodies, as if they were themselves elements. The names 

 of these compound radicals, as they are termed, are formed by affixing 

 to some name which denotes their origin the termination yl (v\i\, 

 matter) : as, for instance ethyl, the radical of ether ; amyl, the radical 

 of amylic alcohol ; acetyl, the radical of acetic acid ; benzoyl, the radical 

 of benzoic acid. The termination yl is indifferently used, whether the 

 radical contains oxygen or not. 



The compounds of radicals with other substances are named 011 the 

 same principles as are applied in the case of organic compounds. For 

 example, chloride of methyl, sulphide of ethyl, nitrate of amyl, hydride of 

 beiunyl, telminm-ethyl, zinc-methyl, 4c. 



Certain radicals, which have an electro-negative deportment, such as 

 cyanogen, mellon, &c., give to their combinations the termination ide, 

 ai cyanide of ethyl, melltjnide of potassium, 4c. 



The termination al is frequently employed to express the names of 

 bodies which are either homologous with aldehyde or are derived from 

 it. Thus : butyral, valeral, clilniral, brumal, &c. 



The termination ole is applied to certain neutral carbo-hydrogens. 

 Ex.': benvjle, cumoU, cymoU, &o. 



The termination ine has been applied to substances of the most 

 heterogeneous nature. Thus we have hamaline, a constituent of the 

 till ii id corpuscles ; stearinc, the combination of stearic acid with glyce- 

 rine ; filirine ; inuline, a modification of starch ; napthaline ; salicine, 

 Ac. The terminal is, however, now generally omitted from all such 

 bodies when they do not possess qualities and composition analogous 

 to ammonia. 



The termination ine has been generally applied to the natural alka- 

 loids extracted from substances of vegetable origin, such as rjuinine, 

 atrnpine, &c. On the dif'overy of compounds possessing the closest 

 analogies with these natural alkaloids, the same termination was 

 assigned to them, as aniline, cyanethine, thiakline, &c. 



A very large number of compounds have been discovered which 

 receinble ammonia, and have hence been called amide bases, or amines. 

 Viewed aa ammonia, in which hydrogen is replaced l>y certain radicals, 



they have received a corresponding nomenclature. A compound 



/ (H\ 

 NC 4 H,, is ammonia f N j H V in which hydrogen is replaced by 



\ ( H/ 



ethyl (C^Hs), and is called ethylainine. An ammonia in which hydro- 

 gen is replaced by phenyl is called phcnylamiiie. The name bimethyla- 

 mine, or dimethylamine, is assigned to an ammonia in which 2 eq. of 

 hydrogen are replaced by 2 of methyl (C 2 H 3 ) ; ethylophenylamine, to an 

 ammonia in which 2 eq. of hydrogen are replaced respectively by ethyl 

 and by phenyl; ethylomethylophenylamine, to an ammonia in which 

 3 eq. of hydrogen are replaced respectively by ethyl, methyl, and phenyl. 

 Certain compounds have a composition analogous to the ammonium 

 salts, and have received corresponding names. Thus, C,,H,.NC1= 



CTT ~* ^0^4 



12 H 5 I 



r 1 TT 



p 2 j_ 3 >NC1 corresponds to chloride of ammonium, and is termed 



cX,J 



chloride of ethylomethylamylophenylammonium. Such names are ex- 

 ceedingly unwieldy, but they possess the advantage of indicating the 

 exact composition of the compounds to which they are applied. 



In certain natural bases, hydrogen can be replaced by radicals, either 

 simple or compound. Thus there are chlorocinchonine, methyle, strych- 

 nine, &o. 



A large class of organic substances is formed by the substitution of 

 hydrogen by an equivalent quantity of chlorine, bromine, hyponitrous 

 acid, &c. Such compounds are called substitution products, and the 

 principles on which they are named is evident from the following 

 examples: bichlorobuti/ric acid (C S H C1 2 4 ) ; bromobenzole (C^H^Br); 

 nitrobenzoic acid (C 14 H 5 (NO,)0 4 ) ; binitrobmzoic acid (C 14 JH 4 (N0 4 '). 1 0. [ ) ; 



cldormnuine Cl2eC1 ; trichloracetic acid (C.HjClOJ, &c. 



CHEMISTRY, from xV fa (chemeia). According to Suidas (in voc. 

 ueia) it was " the making of silver and gold," or what is now more 

 generally known by the name of alchemy. [ALCHEMY.] Suidas adds 

 that Diocletian burnt all the ancient books of the Egyptians on 

 chemistry (as above explained), in order that the Egyptians might no 

 longer be able to acquire wealth by the practice of this art, and thus be 

 encouraged to resist the Romans. We may probably infer from tlu's 

 that cherne'ia is an Egyptian word; and if so, its resemblance to 

 Cham or Chem, the genuine name of the country, is a confirmation of 

 this supposition as to its origin. But whatever may have been the 

 original meaning of the word, it no longer includes the imaginary 

 process above-mentioned. Various definitions of its present meaning 

 have been given. Gmelin defines chemistry as the science which 

 treats of the combination of dissimilar bodies into homogeneous masses, 

 and of the separation of dissimilar bodies from homogeneous masses.. 

 According to Thomson, "the object of chemistry is to determine 

 the constituents of bodies, and the laws which regulate the combina- 

 tions and separations of the elementary particles of matter." ' Inorganic 

 Chemistry,' vol. i. p. 1 . 



The materials composing our globe, when brought into contact 

 under favourable circumstances, are capable of undergoing certain 

 changes, by which their physical properties become modified or 

 entirely altered. The observation of these changes, the discovery and 

 study of the laws which govern them, and the forces or conditions which 

 modify, promote, or retard them, constitute the science of chemistry. 



From the very nature of the operations hi which man is compelled 

 to engage for his own sustenance, comfort, and defence, as well as from 

 the multitude of changes of the nature just mentioned, which are con- 

 stantly occurring at the surface of our earth, it is evident that even 

 the most ancient races could not be wholly ignorant of chemical phe- 

 nomena, although the classification of these phenomena, and the 

 deduction of the laws regulating and governing them, have been 

 almost entirely -the work of the past and the present .century. 



The science of chemistry cannot boast of any noble origin : on the 

 contrary, it sprang from delusion and superstition, and was fostered 

 by deception and credulity ; hence its early history presents us with 

 little that is truly interesting, sublime, or admirable. Many attempts 

 have been made to trace the origin of chemistry to Tubal Cain, who, 

 as an instructor of every artificer in brass and iron, is supposed to 

 have had a considerable amount of chemical and metallurgical know- 

 ledge. Others attribute it to Hermes Trismegistus, whose son, 

 Mizraim, was said to have first colonised Egypt, and though such 

 statements may call a smile to the lips of those deeply versed in 

 ancient lore and modern archaeological research, yet, involved as is the 

 early history of this science in dark obscurity, the Sacred Writings, 

 as well as the relics of the wonderful race that once peopled Egypt, 

 bear strong testimony that they were acquainted with many chemical 

 processes, which they employed for the preparation of colouring 

 matters for their pottery, and in the embalming of their dead. The 

 coloured glass beads with which their mummies are frequently deco- 

 rated show also that they were not strangers to the art of glass-making. 

 These, and other instances which might be mentioned, do not, how- 

 ever, allow us to conclude that chemistry was known and cultivated at 

 this remote period as a science ; on the contrary, its applications were 

 probably only accidental and isolated, being practised by the various 

 workmen empirically, and without any knowledge of the peculiar 

 forces upon which the processes depended. By degress, however, as 



