August 19, 1968

Professor Art Campbell

Harvey Mudd College

Clairmont, California

Dear Art:

I am writing to suggest that you reconsider the matter of the designation of state of aggregation of substances.

I have suggested earlier that the state of aggregation be attached to the chemical formula by using parentheses and a suitable letter on the same line as the formula, with the letter in Roman type, rather than italics. You are using parentheses and an italicized letter, and putting the whole thing in as a subscript.

The matter of whether the letter should be in Roman type or italics is not very important. In my books in the past I have used italics, but I have decided now to use Roman, since the trend of usage seems to be in this direction.

The matter of having the parentheses as a subscript is different. Here there is no doubt about the weight of usage. I pointed out that about 95 percent of books put the parentheses on the same line. An example is Chemistry, an Experimental Science. One exception is Wall's book.

Unless there is a good argument for deviating from convention, I think that a textbook should follow the convention—the convention is used in the student's high school text and used in the standard reference books and other textbooks that he will have contact with later.

It seems to me that it is illogical to put the parenthensis as a subscript. For example, if you have the formula for molecular oxygen, 0 , with (G) as a subscript, it looks as though the parenthetical letter is intended to modify or describe the subscript to which it is attached, which is the number 2. It is, instead, intended to describe the substance itself, which is C> ; and accordingly the logical place to have it is on the same line as the formula itself, not as the subscript numeral.

Sincerely,

Linus Pauling

LP:jj

cc: Mr. Stanley Schaefer