Note 1: (window tax) There was indeed a tax on each window in a house. This led to some home owners bricking up some of their windows to avoid paying the taxes. If you have seen the A&E/BBC production of Pride and Prejudice, you might have noticed that some of the ground-floor windows inside the courtyard of Pemberley (the real Lyme Park in Cheshire) have been bricked up. This may have been done to avoid the tax man.
You may also have noticed Mr. Collins delighting in the number of windows at Rosings Park. Part of the boast is that the de Bourgh family is so well off, it doesn't need to concern itself with a paltry little tax.
Note 2: (ærea) Ever seen "area" spelled with the æ diphthong before?
Note 3: (Blair's) Dr. Hugh Blair was an Eighteenth Century preacher who published five volumes of sermons between 1771 and 1801. He was a minister of the High Church, and professor of rhetoric and belles lettres at the University of Edinburgh.
Blair's Sermons are also mentioned in Chapter XXIX of Thackeray's "Vanity Fair".
Becky was very respectable and orderly at first, but the life of humdrum virtue grew utterly tedious to her before long. It was the same routine every day, the same dulness and comfort, the same drive over the same stupid Bois de Boulogne, the same company of an evening, the same Blair's Sermon of a Sunday night-the same opera always being acted over and over again: Becky was dying of weariness, when, luckily for her, young Mr. Eagles came from Cambridge, and his mother, seeing the impression which her little friend made upon him, straightaway gave Becky warning.
And in Sir Walter Scott's "Guy Mannering", Chapter XXXVII.
'Not at all, my dear, sir,' answered Colonel Mannering-'I am delighted to put myself under your pilotage. I should wish much to hear some of your Scottish preachers whose talents have done such honour to your country-your Blair, your Robertson, or your Henry; and I embrace your kind offer with all my heart.-Only,' drawing the lawyer a little aside, and turning his eye towards Sampson, 'my worthy friend there in the reverie is a little helpless and abstracted, and my servant, Barnes, who is his pilot in ordinary, cannot well assist him here, especially as he has expressed his determination of going to some of your darker and more remote places of worship.'
Note 4: (furlong) A furlong is equal to 1/8th of a mile, or 201 meters.
Note 5: (ha-ha) A ha-ha is a hidden fence system. A trench would be dug and lanscaped, and in the bottom of the trench, a fence would be hidden (in part to keep the sheep where they are supposed to be). From a distance, one might see a slight variation in the ground, but would not see anything of the fence. It is believed it was named because it would surprise a person who came across such a fence.
The American Heritage Dictionary gives the following definition: "A moat, walled ditch, or hedge sunk in the ground to serve as a fence without impairing the view or scenic appeal."