§ =23.= The number of the unaccented syllables of the thesis was formerly believed to depend entirely on the choice of the individual poet.[65] Sievers first put this matter in its right light by the statistics of the metre.[66] He showed that the hemistich of the Old English alliterative line is similar to the Old Norse four-syllable verse, and is as a rule of a trochaic rhythm (–́ × –́ ×). The proof of this is that in _Beowulf_, for instance, there are 592 hemistichs of the type –́ × | –́ × (as _hȳ́ran scólde_, 10), and that in the same text there are 238 of the type –́ × × | –́ × (as _gṓde gewýrcean_, 20; _hḗold þenden lī́fde_, 57), making 830 hemistichs with trochaic or dactylic rhythm, as against eleven hemistichs of similar structure but with an unaccented syllable at the beginning, × | –́ × (×) | –́ ×, and even four or five of these eleven are of doubtful correctness. From these figures it seems almost beyond doubt that in the type –́ × (×) | –́ × the licence of letting the hemistich begin with an unaccented syllable before the first accented syllable was, generally speaking, avoided. On the other hand, when the first accented syllable is short with only one unaccented syllable as thesis (⏑́ ×), we find this initial unaccented syllable to be the rule, as _genúmen hǽfdon_ Beow. 3167 (× | ⏑́ × | –́ ×), of which form there are 130 examples, while, as Rieger noticed, ⏑́ × | –́ × is rare, as in _cýning mǣ́nan_ Beow. 3173. It is perhaps still more remarkable that while the form –́ × × | –́ × occurs some 238 times, a verse of the form × | ⏑́ × × | –́ × is never found at all. The numerical proportion of the form –́ × | –́ × (592 cases) to –́ × × | –́ × (238 cases) is roughly 5 to 2, and that of × | ⏑́ × | –́ × (130 cases) to × | ⏑́ × × | –́ × (no cases) is 130 to nothing. The quantity of the second arsis is, as bearing on the prefixing of unaccented syllables to the hemistich, much less important than the quantity of the first arsis. Hemistichs of the type –́ × | ⏑́ × occur 34 times, and in 29 cases the last unaccented syllable is a full word, either a monosyllable or a part of a compound. The same type, with an initial unaccented syllable × | –́ × | ⏑́ × also occurs 34 times, but then the last syllable is quite unaccented. The proportion of the form –́ × | –́ × to the form × | –́ × | –́ × is 592 to 11, and that of the form –́ × | ⏑́ × to × –́ × | ⏑́ × is 34 to 34, a noticeable difference. Further, it was formerly supposed that the number of unaccented syllables following the accented syllable was indifferent. This is not the case. The form –́ × × |–́ × is found 238 times, and the form –́ × | –́ × × only 22 times. Many of the examples of the latter form are doubtful, but even counting all these the proportion of the two forms is 11 to 1.