Dumas dates and figures

I note that in Chapter 83 of "Vingt Ans Après", Athos and Aramis find a drawing left by d'Artagnan at Peronne with the sinister message "We are being followed" and, understandably disquieted even though the trail they are following is already cold, proceed to gallop frantically for three or four hours until they encounter the giant boulder moved by Porthos, under which the next message lies. We don't know what time they arrived at Peronne, but since they don't appear to have spent the night there and only discovered d'Artagnan's drawing as they were leaving after a failed search of the town, it can scarcely have been before mid-morning at the earliest, especially since the date is early March and they will not have started travelling until winter daybreak.

After galloping all the way from Peronne, they are obliged to allow their horses three hours' rest, and it takes them a further six hours of riding to reach Compiègne, where they learn that d'Artagnan and Porthos were overtaken and captured. This adds up to a minimum of twelve hours' travel, at the end of which we are told that they dined hastily in order to be able to set out again immediately that night (since Blaisois and Grimaud are left behind with instructions to take the spent horses back to Paris "tomorrow") on hired horses. Even if we assume that they set out at dawn from some nearby hostelry and reached Peronne at 8am or thereabouts, it must have been well and truly dark by this point!

( The journey continued further )

( Grimaud and Mme de Longueville )