PROFESSOR KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
75 
observation. This difficulty consists in knowing what constitution is to be assigned 
to the body in question for the solid or liquid condition ; this constitution, from the 
conclusions derived from his theoretical considerations, would often be different from 
that which the body has in the state of gas or vapour. His considerations led him 
to assume the atomic weights of many elements different from those which Berzelius 
had given : Avogadro described the atoms, to which the weights assumed by him refer, 
as thermal atoms. 
6. B. Hermann published in 1834 a memoir “ On the Proportions in which Heat 
unites with the Chemical Elements and their Compounds, and on the Combining 
Weights considered as quotients of the capacity for Heat of Bodies into their Specific 
Gravities”* * * § . He gives there a great number of determinations of the specific heat of 
solid bodies (of a few elements, but chiefly of compound bodies). He made a few ex- 
periments in which he used Lavoisier and Laplace’s calorimeter f ; but by far the 
greater number of determinations are made by the method of cooling Many of his 
results approach very closely to those which are at present considered accurate, but 
they are in so far untrustworthy that a considerable number among them are decidedly 
incorrect. 
As for Hermann’s theoretical results, it must be borne in mind that, regarding 
matter as he does, not from the point of view of the atomic but of the dynamical 
theory, he puts the idea of combination weights in the place of the idea of atomic 
weights. The propositions which he endeavours to establish are the following. The 
quotients obtained by dividing the specific gravities cf the elements § in the solid state 
by their specific gravities in the gaseous state, are either equal or stand to each other 
in simple ratios ; they are 1,2 15 times as much as a certain base. The 
same is the case with the products of the specific gravities of the solid elements into 
their specific heats, that is, with their relative heat ; and the number indicating the 
multiple for a given element is the same for both the above relations. It follows from 
this that the combining weights m of the elements are proportional to the quotients of 
their relative heats into their specific gravity in the solid condition ; that the products 
of the specific heats and the combining weights for different elements are equal to a 
constant, and that from the known combining weight of an element its specific heat in 
the solid form may be calculated (it is equal to 0 ' 3 m 7 5 , where m is the combining weight 
of the substance in question referred to oxygen = 1). For several elements (phosphorus, 
* Nouveaux Memoires de la Societe Imperiale des Naturalistes de Moscou, vol. iii. p. 137. 
+ Hermann tried to alter this apparatus so as to make it serve for measuring the change of volume which 
takes place when ice melts ; but he did not further follow this application of the modified apparatus. 
X They are found not quite complete in Gmelin’s £ Handbuch der Chemie,’ 4 Auflage, in the Tables, 
pp. 215-218 et seq. 
§ Hermann considers that the specific gravities of the elements in the state of gas or vapour are either 
obtained by observation, or may be theoretically deduced by assuming that they are in the ratio of the com- 
bining weights. 
