68 System of Chemistry, by Prof. Berzelius. 



other compounds analogous to them ; since it is deemed sufficient to 

 mention the radical as if it existed in the compound in its metallic 

 state. Ordinarily we say, sulphate of lead, not sulphate of the oxide 

 of lead. This last mentioned expression is resorted to, only where 

 great precision is desirable. In such cases, it might be better to say 

 sulphate of the oxybase of lead. So long however as the electroneg- 

 ative combinations of oxygen are designated as oxacids, and the elec- 

 tropositive as oxides, it seems to be incorrect, not to use analogical 

 terms in the case of analogous compounds, formed by other pre-emi- 

 nently electronegative principles ; and assuming the definition above 

 stated, to be justified by modern practice, it follows, that in order to 

 entitle the electronegative and electropositive ingredients of the double 

 salts of Berzelius, to be classed, the latter as bases, and the former 

 as acids, it is not necessary to appeal to the highly interesting and 

 important experiments of Bonsdorf, confirmed in some instances by 

 the testimony of Berzelius himself, proving that the attributes of acid- 

 ity (as heretofore defined) exist in the one case, and those of alka- 

 linity in the other. My definition is founded upon the conviction 

 that these characteristics have not latterly been deemed necessary to 

 acids, and that in bases, they never were required ; having, as re- 

 spects them, only served as a means of subdivision, between alkahne 

 oxides and other bases. 



Chemistry owes to Berzelius much valuable information respecting 

 the compounds formed by the substances which he calls "AoZo^ewe;" 

 especially respecting the combination formed by fluorine, with boron, 

 and silicon, and the ^'double salts" as he considers them, formed by 

 the union of two " halogene snlts,''^ he. While in the highest degree 

 interested in the facts which he has ascertained, it will be inferred 

 from the premises, that I do not perceive that any adequate line of 

 distinction can be drawn in this respect between the simple salts form- 

 ed by oxacids and oxybases; and the double sa]ts formed by his 

 "halogene" elements. — Agreeably to the definition which 1 have ven- 

 tured to propose, in a combination of this kind, the electronegative salt 

 would play the part of an acid, while the electropositive salt would 

 perform that of a base. 



In common with other eminent chemists, he has distinguished acids 

 in which oxygen is the electronegative principle, as oxacids, and 

 those in which hydrogen is a prominent ingredient as hydracids. If 

 we look for the word radical, in the table of contents of his invalua- 

 ble Treatise, we are referred to p. 218, vol. 1st., where we find the 



