178 Mr. H. Croft's Abstract of Dr. H. Kopp's Researches 



deavoured to avoid those faults which he blamed in Schroder's 

 work, and which consist principally therein, that Schroder 

 made too great a number of arbitrary assumptions and sup- 

 positions, and, notwithstanding, considered the results of his 

 theory as absolutely certain, forgetting that the probability 

 of a theory becomes the less in proportion as the number of 

 assumptions on which it is founded becomes greater. Dr. 

 Kopp, on the contrary, .believes that on this subject no abso- 

 lutely true theory can at present be made, but still a very 

 probable one may be proposed, whose probability is proved 

 by its explaining, by means of the fewest possible assumptions, 

 the greatest possible number of experimental facts. The 

 views of Dr. Kopp, which are explained in the following 

 paper, differ considerably from those of Schroder ; but they 

 embrace a much greater number of compounds, which they 

 fully explain with very few assumptions. 



It will be better first of all to give a tabular view of the 

 atomic volumes of the simple bodies as obtained by dividing 

 the atomic weights by the densities. These atomic volumes 

 of simple bodies in an isolated state are called by Dr. Kopp 

 the " Primitive atomic volume," to distinguish them from 

 those which elements possess when they enter into combina- 

 tion ; for in compounds they may be contained with atomic 

 volumes quite different from their primitive ones. We will 

 here give the atomic volumes as adopted by Dr. Kopp; the 

 atomic weights (which are always those of Berzelius, with the 

 exception of that of bismuth, which is taken as 1330 accord- 

 ing to the latest researches) may be left out, as well as the ob- 

 served densities, which agree very well with those calculated 

 from the adopted atomic volumes. Cyanogen has been 

 added. 



Table I. — Primitive atomic volumes of the simple bodies, 

 and of their calculated densities. 



I 



