Dear Sir (Source)
Your letter to Genl Dumas was deliverd by me to his lady from whom in consequence of it I receivd during my stay in Paris the most polite & flattering attentions. She deliverd me the inclosd answer which was written in Copenhagen & forwarded to her. Having heard that Mrs Marshall is in Winchester I shall immediately set out for that place.
Permit me Sir to acknowledge the receipt of your very polite & obliging letter in answer to that which I did myself the honor to address to you from the Hague.
1.
Would someone please expound the differences between "that which" and "which"? Why not "...polite & obliging letter in answer to which I did myself the honor ..." ?
2.
Is the expression "to do the honour to someone" or "to do someone the honour" or both? Why not the other?
3.
http://dictionary.reference.com/browse/do+honor+to says
I. to show respect to. II. to be a credit to.
Would someone please explain how "to do honour to" engenders these meanings? Is "do" a synonym of "bestow/convey/impart" here?
4.
How would John Marshall be doing himself the honour to address a letter to George Washington from the Hague?