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"CONTRIBUTIONS TO THERMODYNAMICS: THE ANOMALOUS HEAT OF VAPORIZATION OF HEPTANE," BY 1. McQUIRG WORDEN WARlNG Arthur D.Little, Inc., Cambridge, Massachusetts
IN 111s paper on "The anomalous heat of vaporization of heptane,"' Dr. McQuirg takes some excellent data and perfectly valid thermodynamic equations and manhandles them to produce very misleading results. His method of fitting a three-parameter equation by choosing three points is inefficient a t best; here i t leads to quite erroneous conclusions. For he takes triplets of points quite close together, so that the experimental scatter is highly magnified. His point 1, for example, lies slightly above the general trend of the Far the article that is discussed here, ses page 347 of this issue.
data; when it is used together with nearby points a greatly exaggerated slope of the curve is calculated. When the other points are chosen farther away, the slope is less exaggerated and approaches a legitimate representation. Dr. McQuirg could equally well have presented a thesis opposite to his present one by starting with a point below the general trend of the data. The behavior he presents is not a measure of the behavior of the heat of vaporization (or the vapor pressure), but simply an indication that the statistical scatter of the d a t i is beginning to be compensated for by the use of a longer "base line" for fitting the curve.
