validation in the hands of 90% of all scientists that ever lived, and that "their reality cannot be ignored in the context of modern ontology." What you are doing here is offering a popularity poll (of the past and present) in opposition to your opponents' philosophical ideas. I n so doing, you do not answer their objections, but do demonstrate your belief that philosophy is not important in man's life. This is why you belittle the debate over the "reality of constructs" and conclude that a teacher improving his knowledge of what he teaches might be more important. But philosophy is of crucial importance for man. It is philosophy which tells us that man is a rational creature, a creature that can use reason to integrate the facts of reality he observes. When a man chooses to do so, he forms concepts. It is these concepts along with the facts they are induced from which constitute scientific knowledge. But without philosophy to tell men how to gain that knowledge, science would be impossible. It is this lack of appreciation for the importance of philosophy which leads you to state that direct sense data usually give no basis for logical thought, when, in fact, they are the sole basis for logical thought (what other data could you appeal to?). It also causes you to undermine metaphysical principles, so that you talk about research intensifying "our knowledge of these constructs." But knowledge is knowledge of reality (which exists apart from man's knowledge and is an absolute), and takes the form of concepts in our minds. This same equivocation was carried over from the preceding sentence where you stated that electrons "cannot be regarded as elements of ultimate reality" for we do not understand them fully yet. Here you are undermining epistemological principles by failing to grasp the idea of concepts as being open-ended mental integrations, specifying some of the characteristics of the existents that are subsumed under them, but not enumerating those existents, nor necessarily specifying all their characteristics. Electrons are electrons, and they exist whether we know everything about them or not. One could not logically maintain even the possibility of their non-existence unless he offeredat least a partial explanation (in terms of an alternative) of all the facts their existence explains. No such alternative explanation has ever been offered. DAVIDSOLAN
Ideal Gas Deflnition
To the Editor: Although I am grateful to Professor Davidson for his sympathetic review of my supplemental paperback, "A Different Approach t o Thermodynamics" (J. CHEM. EDUC.44, 700 (1967)), his comments involving the nature of the ideal gas might have given readers of the review the wrong impression of the book's treatment.
My position is that the nonexistent ideal gas is defined by the ideal gas equation, P V = nRT. Implicit in this equation are the two well known assumptions: that the particles have no forces acting among them and that these particles have no volume. According to this position, the nonexistent ideal gas is a collection of points that can have only one kind of energy-translational energy. Therefore, the statements in the book that the ideal gas has no "chemical composition" and that for the ideal gas C , is 3/2 R are not "inaccuracies," as Professor Davidson states, but consistent consequences of one way of defining the ideal gas.
Anticipating Valences
To the Editor: I n a recent article Eichinger (J. CHEM.EDUC.,44, 689 (1967)) writes on "Anticipating 'Valences' from Electron Configurations" which should be more precisely named "Anticipating 'Cationic Valences' from Electron Configurations" or as noted in a footnote in his paper, "The Ionization of Metals." His is the same general approach I use in my General Chemistry classes and I find it to work quite well. Additional notes may be made to his article. (1) As the metal gains in positive charge (i.e., loses electrons), the ionization potential increases so that the ionization potential for the 4th electron, for the Ma+to go to MA+, is in the order of 50-120 ev, for non-rare earth type elements (BAILER,MOELLER,AND RLEINRERG, "University Chemistry," Heath and Co., Boston, 1965, p. 166) which seems to be a prohibitive amount of energy. (2) The rules of stability are partially the consequence of the "filled sublevel" and "filled level" rules for added stability. (3) The "rules" given by Eichinger do not specifically apply to elements of the rare earths of type 4f and 5f where, for instance, 4f electrons areremoved before 5s or 5p electrons, but otherwise the electrons with tht! hight!vT pri14plc qu:inrnm 1111n1bcr :trcrcmowtl first (C;or~r.v."I~~ore:~~~ic. Her~c~iol~s:t~:d Strur~nr~."Hoh. ~ i n e h a r t and , Winston, New York, 1962, p. 21j in the rare earths type 4f elements; and the energies of the 5f and 6d subshells are nearly the same such that the orbitals occupied in ions or complexes of the rare earths type 5f elements may change as the valence state or n e ture of the complexing group changes (ibid., p. 115). Most of these elements have as the most common valence number +3 with certain of them also having stable +2 to +6 valence numbers. With little difficulty a student may master by memorization the common valence states for anions. Thus the need for a method of prediction of valence states of anions is not as essential as the need for prediction of valence states of cations. CHARLES E. CARRAHER, JR. UNIVERSITY OF SOUTH DAKOTA
YE~ILLION, SOUTH DAKOTA 57069
Volume 45, Number 5, Moy 1968
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