But the main form of internal evidence, what is usually meant by that term, is the testimony in the character and style of the plays themselves as to the maturity of the man who wrote them. Just as the stump of a tree sawn across shows its age by its successive rings of growth, so a poem, if carefully examined, shows the rings of growth in the author's style of thought and expression.
The simplest and most tangible form of this evidence is that which is found in meter. If we read in order of composition those plays which we have already succeeded in dating, we shall find certain habits of versification steadily growing on the author, as play succeeded play.
In the first place, most of the lines in the early plays are 'end-stopped'; that is, the sense halts at the close of each line with a resulting pause in reading. In the later plays the sense frequently runs over from one line into another, producing what is called a 'run-on' line instead of an 'end-stopped' one. By comparing the following passages, the first of which contains nothing but end-stopped lines and the second several run-on lines, the reader can easily see the difference.
(a) From an early play:—
"I from my mistress come to you in post:
If I return, I shall be post indeed,
For she will score your fault upon my pate.
Methinks your maw, like mine, should be your clock,
And strike you home without a messenger."
—Comedy of Errors, I, ii, 63-67.
(b) From a late play:—
"Mark your divorce, young sir, [end-stopped]
Whom son I dare not call. Thou art too base [run-on]
To be acknowledg'd. Thou, a sceptre's heir, [end-stopped]
That thus affects a sheep-hook! Thou old traitor, [end-stopped]
I am sorry that by hanging thee I can [run-on]
But shorten your life one week. And thou, fresh piece [run-on]
Of excellent witchcraft, who of force must know [end-stopped]
The royal fool thou cop'st with...—"
—Winter's Tale, IV, iv, 427-434.
Since Shakespeare keeps constantly increasing his use of run-on lines in plays for which dates are known, it seems reasonable to assume that he did this in all his work, that it was a habit which grew on him from year to year. Hence, if we sort out his plays in order, putting those with the fewest run-on lines first and those with the greatest number last, we shall have good reason for believing that this represents roughly the order in which they were written.