70-1. The following were appointed a committee on organization: John Smith (chairman), Henry Jones, and William Brown.
It seems surprising that good writers will adopt the punctuation of No. 70, and use it when it tends to obscure the sense. As illustrative of this point, we give a sentence from the current issue of the Literary Digest:
71. This new magnet is used for the study of light, the motions of electrons, the smallest components of matter, and the minute movements in the interior of an atom.
For the sake of clearness, which is a chief object of punctuation, the sense relations of the things named in this sentence as objects of study should be shown by the punctuation. As “electrons” are “the smallest components of matter,” the punctuation should reveal the fact:
71-1. This new magnet is used for the study of light, the motions of electrons (the smallest components of matter), and the minute movements in the interior of an atom.
By reserving dashes for the large groups of words which are purely parenthetical in nature, but are tied to what precedes by a connective, generally a conjunction or a preposition, we do not violate the fundamental meaning of either the dash or the marks of parenthesis; and therefore when we meet either mark its meaning is unmistakable. In short, we do not make a mark serve an additional and unnecessary use, and so render it more difficult to interpret as a sign-board.
When we speak of the “fundamental” meaning of a mark, we refer to the meaning implied in its name, the name, of course, being descriptive of a feature of the language which is to be pointed out by the mark. The word dash, as has already been said, points out that the writer has dashed aside, as it were, in his line of thought, and is going to “parenthesize” something, keeping his thought, however, grammatically connected with what precedes. We violate this principle in the use of the single dash exemplified in Sentence 33, just as we violate a fundamental principle in the use of the parentheses in No. 70-1. We think there is no objection to the former use of the dash; for it serves a good purpose, and its meaning can hardly be mistaken. The relation indicated by the comma and dash is suggested before the mark is reached, as, in Sentence 33, details are suggested by the words “three original parties.”
The indiscriminate use of dashes and parentheses for commas has become quite common; but, after a very careful study of language thus punctuated, we can find no justification or excuse for such usage. It may give the writer a choice of marks, but it gives no light to the reader. It is too much like using either red or yellow for a danger-signal when red better answers the purpose.
Although the differentiation between commas and parentheses is at times somewhat difficult, generally it is very easy. The following sentences will illustrate common uses of the marks where the shades of meaning are nice, but unmistakable:
72. Ian Maclaren (Dr. John Watson) wrote “Beside the Bonnie Briar Bush.”
73. Ian Maclaren, a noted Scotch minister (Dr. John Watson), is the author of “Beside the Bonnie Briar Bush.”
74. Ian Maclaren (the pen-name of Dr. John Watson) is unmistakably Scotch.