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XXXVITI. 
A NEW THERMO-CHEMICAL NOTATION. By JAMES HOLMS 
POLLOK, B.Sc. 
[Read Aprit 17; Received for Publication Aprit 19; Published Juzy 6, 1901.] 
In the study of Thermo-chemical Equations a good deal of 
difficulty is experienced in clearly and briefly expressing the 
various quantities under consideration, so as to retain a view of 
the actual chemical and physical changes taking place, and like- 
wise of the quantity of heat evolved or absorbed thereby. No 
doubt, in print, one can readily state in the preamble the particular 
states of the various reagents and products, and tabulate the 
thermal quantities in a clear and intelligible manner ; but, in the 
actual calculations necessary to arrive at these tabulated results, 
the tendency to confusion is very great indeed, and though the 
methods of Thomsen or Berthelot have been found to work well in 
the past they are scarcely now sufficient. Thomsen’s method of 
statement is logical and correct from a purely thermal point of 
view, but is exceedingly confusing from a chemical point of view. 
Berthelot’s method, on the other hand, is clear, because the chemical 
equation is retained almost without alteration, but as it is not an 
algebraic equation, it is only a statement of results, and gives no 
facility for further calculation. What is required is a correct 
algebraic equation which will at once indicate clearly the chemical 
and physical changes under consideration, together with the heat 
evolved in the reaction. Hach definite quantity of matter or 
energy being indicated by a definite symbol, so that the sum of 
the system before and after the reaction will be clearly set forth. 
Such an equation would obviously be capable of all the processes 
of algebra for the determination of unknown terms. In the 
thermal expression of any ordinary chemical reaction it is necessary 
to take account not only of the state of combination of all the 
reacting elements, both before and after the reaction, but also of 
the precise physical state of each reagent and product. Now the 
