NOMENCLATURE AND NOTATION, CHEMICAL. 



621 



Table of Elements, and Chemical Values. 



Of course, the atomic volume and molecular 



constitution of many elements in respect to 

 which these particulars are not given in llio 

 table, are regarded as being known, with 

 greater or less certainty, being inferred in ac- 

 cordance with principles already indicated. 

 Further, some variation still exists between dif- 

 ferent authors in regard to the atomic weights 

 and quantivalential coefficients to be assigned 

 to certain of the elements. Odling, for exam- 

 ple, agreeing in the other instances with the 

 values above, places lead and palladium among 

 tetrads, and thallium among triads; while 

 Strecker regards the last-named element as pre- 

 senting analogies with both monatomic and 

 triatomic elements, and raises a question as to 

 the invariableness of the atomicities. 



It may here be remarked, that the symbols 

 employed throughout this article have the 

 equivalential (atomic -weight) values given in 

 the table above, so far, at least, as the doubling 

 of the equivalents of certain elements O., S., 

 C., etc. is concerned. 



Nomenclature. Besides the general interest 

 recently taken in the theory of chemical com- 

 bination and equivalents, much attention has 

 during a very few years past been given to the 

 special subject of the nomenclature to be era- 

 ployed in case of compound bodies, and for the 

 present at least, of those particularly of an in- 

 organic character. 



Professor A. "W. Williamson delivered before 

 the London Chemical Society, December 15, 

 1864, a short discourse on the subjects of "Chem- 

 ical Nomenclature and Notation ;" and, a large 

 part of that and of a succeeding evening having 

 been devoted to discussion of the views advanced, 

 the result was a very general approval, in the 

 main, of their purport, by the distinguished 

 chemists present. Of course, as the title of the 

 leading discourse indicates, principles relating 

 to the symbolic expression of compounds, as 

 well as to their naming, were considered. Some 

 of the more important views advanced on the 

 occasions mentioned, as well as in certain pub- 

 lished articles on the same subjects, will be 

 embodied in this place, but without following 

 the precise order of their presentation. 



Adopting, as now usual, the volume of 16 

 parts by weight of oxygen as the relative unit- 

 volume of bodies in gaseous form, Professor 

 Williamson had, for his absolute measures of 

 both volume and weight, fixed on units differ- 

 ent from those proposed byllofmnnn. As the 

 standard volume, he takes 11.19 (for most 

 practical purposes, say 11.2) litres, selecting 

 this for the reason that, measured in oxygen gas 

 at OC. and 760 mm. pressure, the weight ob- 

 tained is just 16 grammes. The selection of 

 this number, which corresponds with the new 

 equivalent weight of oxygen, renders compara- 

 tively easy, when the molecular weights of the 

 latter are once known, all calculations relative 

 to the actual weights and volumes of gaseous 

 and volatilized bodies. 



The lecturer's principal purpose, however, 

 was to suggest the adoption in scientific 



