Many of these, and similar names applied to electro-negative elements, are 

 often misused by distinguished authors who have adopted the atomic notation; 

 for instance, sesqui to designate the combination of. six atoms of a halogen 

 with two atoms of carbon, or of a biatomic metal. 



The comparatively recent discovery of a great number of organic compounds, 

 so called, required the coinage of many new names to designate radicals. 

 Simultaneously the attempt was first made by German chemists to state 

 definitely by prefixes the number of " equivalents" of each element in com- 

 bination, which has resulted in the formation of names of a frightful length, 

 scarcely pronounceable and seldom remembered. A complete catalogue of the 

 chemical bodies now known would embrace several thousand terms. The no- 

 vice, misled at first by common and commercial names, like " milk of lime," 

 "sugar of lead," "cream of tartar," "oil of vitriol," and "butter of an- 

 timony," but who had advanced far enough to find no sulphur in sulphuric 

 ether, no copper in copperas, no lead in black lead, no soda in soda water, and 

 to be assured that "Dutch liquid" is not imported from Holland, might look 

 with interest and wonder on the accumulated names approved by the highest 

 authorities, and enquire whether this magnificent patchwork could be of much 

 service as a chemical chart. To a negative reply, should be added " Yet a 

 substitute for the whole has been provided by the Notation." 



The introduction of chemical symbols by BERZELIUS marks an era of progress 

 quite as plainly as the first employment of Arabic signs and numerals in the 

 mathematics. The notation is now frequently employed to the exclusion of 

 chemical names, in oral as well as written communications. Its general adop- 

 tion forty years ago, with the atomic signification originally attached to it by 

 BERZELIUS, would have prevented the confusion of terms and signs now con- 

 sequent upon the conformation of the atomic volume of gaseous elements to 

 the one standard. BERZELIUS barred certain letters, to signify that one-half the 

 combining weight was the atomic weight ; in other words, that the so-called 

 " equivalent" contained two atoms. GERHARDT, on the other hand, used the 

 same mark to denote that the combining weight must be doubled to express 

 the atomic weight. MILLER, in the third edition of his " Elements of Che- 

 mistry," designates the old notation in the usual way, and the new notation by 

 italic capitals; while WATT*) in his " Dictionary of Chemistry," still in pro- 

 cess of publication, just reverses MILLER'S arrangement. 



The following symbols, representing a molecule of water according to three 

 different views, will explain what induced BERZELIUS, who measured volume 

 and atomic weight on the oxygen scale, to halve the symbols representing the 

 combining proportion of hydrogen ; and why GERHARDT, who simplified mea- 

 surements by making the hydrogen atom the unit of weight and bulk, was led 

 to double the value of the symbol for oxygen, without knowing to how many 

 other symbols the doubling process would finally be applied. 



DALTON. BERZELIFS. GERHARDT. 



(2 vol.) H (1 vol.) \ {; J | 1 vol. '\ |; H| 1 vol.= H 2 O 2 . 



1+8 = 9. .5+. 5+8 = 9. 14-1 + 16 = 18. 



No inconsistency arises in the interpretation of these symbols ; and although 

 grave objections have been made by HERSCHEL and ODLING to the mingling of 



