ON EVAPORATION AND DISSOCIATION. 
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and an indication of this may possibly be seen with succinic acid. Or it may give a 
curve with an abrupt change of direction, as in C, fig 7, and phthalic acid may afford 
an example of this. Or, lastly, the curve may be indistinguishable from an ordinary 
vapour-pressure curve (C, fig. 8), as is the case with most substances. 
§ 84. Influence of one of the products of dissociation on the amount of dissociation .— 
The results of Horstmann, Moitessier and Engel, and Isambert have shown that 
the presence of excess of one of the products of dissociation diminishes the amount of 
dissociation. Their experiments were made by introducing a known quantity of one 
MDCCCLXXXVI. R 
