In the Introduction to The League of Youth, mention is made of a ‘usually long’ pause before publication of the work, but based on the following discussion, the word was certainly meant to be ‘unusually’.

Volume I of this series included errata for each succeeding volume, and noted one correction for Volume VI. On p. [288], ‘railways’ should have been ‘railway’. The correction is applied here.

[xii.15]in the second act[./,]Replaced.
[xvi.6]a small [c]ollectionRestored.
[xvi.22]to the [un]usually long pauseAdded.
[11.10]Oh yes, with pleasure[.]Added.
[13.2]What[!]Unclear, but probable.
[21.27]Adventurer and d[a/e]magogueReplaced.
[30.30]Me[./,] Chamberlain?Replaced.
[36.30]this terrible storm?[”]Added.
[37.2]several years ago[.]Added.
[42.2]it has been delightful[.]Added.
[48.29]Yes, I am[.]Added.
[98.9]Doctor, what have you done[?]Added.
[109.8]nonsensical prejudices[.]Added.
[109.18]You are an adventurer[,]Added.
[116.24]higher interest on loans[.]Added.
[122.7]We shall soon find that out[.]Added.
[135.18]One would suppose so[.]Added.
[150.24]Yes[,] look closely at it.Added.
[171.9]I am an old hand at prophecy[.]Added. Perhaps semi-colon.
[182.27]about the Chamberlain[.]Added.
[183.26]Asla[sk/ks]en.Transposed.
[188.24]what has happened at Stonelee[./?]Replaced.
[190.28]be good enough to drop that title[.]Added.
[210.20]the order of the day[.]Added.
[214.4]What intrusivenessRemoved.
[245.6][r]emember I am quite newAdded.
[247.20]no one knows exactly about that[,]Added.
[261.28]Mr[.] Bernick.Added.
[288.22]railway accidentsRemoved, per Errata.
[307.14]why did you think I wou[ld] come?Restored.
[324.27]Not a word more to-day[!]Added.
[329.19]It was complet[e]ly repairedInserted.
[336.10]not a halfpenny was missing[.]Added.
[351.14]Aha, he has been here[.]Added.
[357.9]prosper with the railway[.]Added.
[365.26]Why, Rummel, what[ is] the meaningRestored.
[373.31]I will take such care of you[.]Added.
[386.29]No, no[!]Added.