Regia utilitas est==regibus utile est.
XLV. Pigrum. Cf. A. 10: pigrum et grave. The Northern or Frozen Ocean, of which T. seems to have heard, though some refer it to the northern part of the Baltic. See Ky. in loc.
Hinc. For this reason, viz. quod extremus, etc.
In ortus. Till the risings (pl.) of the sun, i.e. from day to day successively. It was known in the age of T. that the longest day grew longer towards the north, till at length it became six months (cf. Plin. N.H. 2, 77), though T. supposed it to be thus long at a lower latitude than it really was, cf. A. 12.
Sonum—aspici. The aurora borealis, some suppose.
Persuasio adjicit. The common belief adds, i.e. it is further believed, cf. His. 5, 5. 13: persuasio inerat.
Illuc—natura. Tantum is to be connected with illuc usque. Thus far only nature extends. So thought the ancients. Cf. A. 33: in ipso terrarum ac naturae fine. Et vera fama is parenthetic. The author endorses this part of the story.
Ergo marks a return from the above digression.
Suevici maris. The Baltic.
Aestyorum==eastern men, modern Esthonians. Their language was probably neither German nor Briton, but Slavonic.