Hi, Ardith Hinton!
I read your message from 16.07.2018 15:52

 AH> I'm not sure what happened there, but the preface to LAST LEAVES
 AH> says that the material originally appeared in various newspapers &
 AH> magazines. I'm wondering whether Leacock mistyped the quotation
 AH> when he saw a deadline looming. In any case he says "I cannot
 AH> forbear to quote again from this high authority" on the page you
 AH> highlighted. If you review what he said +/- two pages earlier
 AH> you'll understand why he didn't go into detail about the source in
 AH> your excerpt.

So, the only authority he had cited earlier was _Encyclopaedia Britannica_
Although it is strange that in

-----Beginning of the citation-----
....I cannot forbear to quote again from this high authority cited
ahead, which thus expounds this aspect of a customary walk.
----- The end of the citation -----

"ahead" means "as stated above".

Bye, Ardith!
Alexander Koryagin
ENGLISH_TUTOR 2018

--- Paul's Win98SE VirtualBox