Pottox—A New Thermo-Chemical Notation. 499 
In any ordinary chemical equation it is obvious that the left 
hand indicates the initial, and the right hand the final states of 
the reacting substances; it is therefore unnecessary to place them 
one above the other, but we may enclose in brackets and place the 
evolved energy sign at the beginning, and the actual thermal 
quantity at the end, and if necessary the physical states beneath, 
thus :— 
E[C.H,O + 60 = 2CO, + 3H,0] = 3825°7K° 
expressing at once the chemical and physical changes, and 
. their accompanying evolution of energy, in the combustion of 
46 grams of alcohol. Now if it is remembered that the left hand 
is the initial and the right hand the final states, we need only 
affix the negative sign to every substance in its initial condition, 
and the positive sign to every substance in its final condition, 
abolish the equality sign within the brackets, and we get a true 
thermal and algebraical equation representing the evolution of 
energy in the transition from one state to the other, so that we 
may subject it to any number of transformations or changes, 
combine it with other equations, or subtract them from it, without 
any fear of error or confusion, thus :— 
E[C,H,0+ 6O0= 200, + 8H,0] = 325:7K° 
— €C,H,O — €60 + 200, + €3H.0 = 825°7K° 
+ €C,H,0O =-0+1885 +207 —-3825°7K° 
= OD QU, 
The foregoing rule is a direct consequence of the general proposi- 
tion that if we proceed from any one state of combination or 
condition to any other state of combination or condition the 
energy evolved or absorbed will be dependent solely on the initial 
and final states, and altogether independent of the particular 
stages by which they are reached. As we agree to select as our 
point of origin the normal condition of the elements at 15° C., we 
know that if E (ys) represent the energy evolved by any sub- 
stances X, Y, Z in their transition from their normal elementary 
state “n’’ to a particular state “a,” and likewise if E, (xyz) 
represent the energy they evolve in their transition to any other 
state “0,” then the energy evolved or absorbed in the transition 
