May 18, 1954

Dr. W. G. Palmer

University Chemical laboratory

Cambridge, England

Dear Dr. Palmer:

I have been surprised by the nature of your review of my book General Chemistry, in the last issue of Acta Crystallographies (7, 381 (1954)).

I myself believe that it is the duty of a reviewer to be candid in criticizing a poor book, and of the editor of a journal to publish critical reviews. On the other hand, because of the damage that he can do through a critical review, the reviewer has a special obligation to be sure that his criticisms are justified.

A reader of your review might conclude, as I at first did, that you have found eight errors or points of serious criticism in the book. On examining them, however, I find that one of the eight is a deviation from customary nomenclature, and the other seven are not errors.

1. You quote my statement "An important aromatic alcohol is phenol." This is an unjustified deviation on my part from the accepted nomenclature.

2. You quote my sentence "Aluminum chloride, A1C1₃ or A1C1₃•6H₂O), is made by treating aluminum or aluminum hydroxide with hydrochloric acid" in such a way as to suggest that it is erroneous. It may well be that the statement should be expanded; it is not, however, erroneous. Possibly you are objecting to my use of the term hydrochloric acid to refer both to the anhydrous gas and to its aqueous solution. Anhydrous aluminum chloride can be made by reaction of gaseous hydrochloric acid with hot aluminum turnings, and the hydrated salt can be made by reaction of aluminum or aluminum hydroxide with the aqueous acid. As to the use of the term hydrochloric acid for the gaseous substance, I may refer to page 167 of the English edition (1926) of Ephraim's Textbook of Inorganic Chemistry.

3. You state that "Throughout the book there is a distracting confusion between the accepted meanings of the terms 'basic' and 'alkaline'." Neither my colleagues nor I are sure as to what you have in mind by this statement; you may be referring to some British usage. My dictionary says that basic may be defined as "showing an alkaline reaction". I have said on page 117 that a basic solution is also called an alkaline solution. Whatever the point is that you are making, it must be a trivial one.

Dr. Palmer -2- May 18, 1954

4. You say that my statement "Formic acid can be made by distilling ants" is a surprising statement. I do not know why you find it a surprising statement; the sane statement is made in many textbooks of organic chemistry, both old and new. For example, the English translation of Richter's Organic Chemistry, 1899, volume 1, page 225, contains the statement that formic acid is found free in ants, and may be obtained by distilling them with water. I am curious to know, in this case as in the others, what the basis for your criticism is.

5. You say that "A reader should, however, be aware that he would be unwise in assuming that all the structures portrayed in the numerous interesting drawings are securely based upon published experimental facts", and mention the tetrathionate ion and hexathionate ion as an example. I am sure that these structures, as shown in the drawing on page 368, are correct (except for the orientation around the sulfur-sulfur bonds, which seemed too minor a point to discuss in this elementary textbook). As a man who has published a hundred structure determinations of molecules and crystals by diffraction methods, I am of course interested in your feeling that a structure can be accepted only after it has been shown to be correct by a diffraction investigation, but I do not have the same feeling myself I think that chemical evidence may also be reliable. I should be glad to learn what you think a possible alternative structure for the tetrathionate ion to be, and I could then tell you my reasons for not accepting it. Moreover, even if one of the many structures described in my book were wrong, would your blanket statements be justified?

6. You say that it is disappointing that an obsolete formulation for bleaching powder should appear on page 269. I would point out that your statement is not really correct, because on page 269 I give a formula which is said only to approximate the composition of commercial bleaching powder. I knew about the determination of the structure of a crystalline substance present in bleaching powder, but I decided that it was not worth while to discuss the matter in greater detail.

7. You say that on pages 11 and 431 there is a faulty explanation of the difficult term "component". My colleagues and I have not found this explanation to be faulty. It is true that I can formulate an argument that can be used as a criticism of my definition, but I can also formulate an argument that can be used as a criticism of any other explanation that I have read. If you would tell me what you find faulty about my explanation, and would also tell me the explanation that you prefer, I should be glad to discuss the matter further.

Dr. Palmer May 18, 1954

. You say that there is degeneration into imprecision in the unfortunate choice of the system hydrogen and bromine to illustrate a photochemical chain reaction on pages 410-411. My colleagues and I are unable to find any imprecision whatever in the discussion of this reaction. I selected this reaction, and the reverse reaction, for discussion after thorough consideration of the alternative photochemical reactions that might have been selected, and I decided that this reaction had advantages over the others, for my purpose. For one thing, there is no other photochemical reaction that is so well understood as this one, and that permits discussion with so little imprecision. This reaction is used as an example of a chain reaction in textbooks of photochemistry. During the 32 years that I have been on the staff of the California Institute of Technology a large amount of research in the field of photochemistry has been carried on here, and I have had the benefit of expert advice in the preparation of my section on photochemistry. I shall look forward to learning what the basis for your criticism is.

I feel forced to conclude that you have not satisfied the obligation of being sure that your criticisms were justified.

Yours truly,

Linus Pauling:W

cc. Prof. P. P. Ewald