Do you know how to protect your idea or invention
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or how to avoid the pitfalls that have lost rights and fortunes for many inventors in the past? Are you familiar with the requirements for patentability? Do you know what steps to take if your idea involves a new use for an old product, is related to prior art, or deals with homologs, isomers, or other analogs? PATENTS FOR CHEMICAL INVENTIONS discusses these and many other pertinent questions. It will help you in your contacts with your employer and your patent attorney and will help you understand patent literature. Though it contains legal abbreviations and terminology, this 117-page book is not a treatise on patent law. It is written for the technically trained man-the research chemist and director-whose very profession provides more than the usual opportunities for conceiving patentable ideas. It presents the broad range of problems concerned with the nature of invention, ownership, inventorship, priority interpretations, documents, signatory formalities during prosecution, etc. Shop rights, employer assignment agreements, the status of the chemist hired to invent, and many other important aspects are discussed.
I n chemically reacting systems, we observe that free energy varies directly with the temperature, indicating the constancy of AS and, hence, of AU, with respect to temperature. The above consideration shows beyond doubt that summation of specific heats of the substances participating in a reaction has the dimension of entropy (6) and corresponds to d ( A F ) / d T , and not to d ( A U ) / d T as was supposed by Kirchhoff. I n the case of the total surface energy, equivalent to the heat of vaporization (when the volume of the liquid is neglected), we note that the sum of the specific heats corresponds to the entropy change at the limiting temperature T,, where AF = 0, and where AU = T,AS. Such a limiting temperature must exist for every system in equilibrium (5). If a reference temperature lower than T , is chosen, the entropy change will result from the summation of specific heats of the components plus the additional entropy change corresponding to the isothermal work necessary to bring the system from the limiting state to the chosen state. The heat of reaction at constant pressure may be obtained by adding to the heat a t constant volume, the heat corresponding to the expansion work, usually BnR T . Conclusion
T h e above exposition demonstrates that thermodynamics problems may not be resolved with the First Law alone, which limits itself to an energy equivalence independent of restrictions imposed by the Second Law. The Kirchhoff equations, which ignore the Second Law, therefore, are without thermodynamic foundation, and their use is questionable and unjustified. REFER ENCES (1) Fishtine, S. H., IND.ENC.&EM. 5 5 (4), 20 (1963). ( 2 ) Giacalone, A , , Gam. Chirn. R a l . 77, 73, 82, 444 (1947). (3) Zbid., p. 8 8 . (4) Zbzd., p. 448. ( 5 ) I b i d . , 81, 185 (1951). (6) Giacalone, A , , Ric. Sn’. 19, 706 (1949). (7) Thornson, G. W., Chem. Reu. 3 8 , 1 (1946).
C0R R ECTION
In the article, “Hot Applied Coal Tar Coatings,” by J. J. McManus, W. L. Pennie, and A. Davies [IND.END. CHEM. 58 (4),43 (1966)], Table I1 was inadvertently printed with the dots reversed. T h e correct pattern is shown below.
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TABLE I I . COATING SYSTEMS
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