"Seven hundred and forty thousand pounds."
   Holmes raised his eyebrows in surprise. "I had no idea that so gigantic a sum was involved," said he.
This grand sum equals more than three-quarters of a billion dollars in today's currency. See  Lawrence H. Officer and Samuel H. Williamson, "Computing 'Real Value' Over Time with a Conversion from British Pounds to U.S. Dollars, or Vice Versa." Economic History Services, September 2005, URL: www.eh.net/hmit/exchange.

"James Desmond is an elderly clergyman in Westmoreland."
Westmoreland is found in Northern England, quite a distance from Devonshire.

"He would be the heir to the estate because that is entailed."
Used in former days to prevent the breakup of large estates by inheritance, entailment limits the right of succession of property to a specific group of heirs, usually keeping it in the male line of direct decent.

"…we shall meet at the 10:30 train from Paddington."
Paddington is the terminus of the Great Western Railway, and lies about a mile and a half west of Baker Street.

"…I spent it at the Museum of the College of Surgeons."
The Museum of the Royal College of Surgeons would be a natural attraction for Dr. Mortimer, considering his interests. It featured an enormous collection of preserved specimens from human and animal dissections performed by John Hunter (1728-1793), fossils, medical instruments, and more. The government purchased it in 1799, and today it can still be visited. For a small glimpse of its vast holdings, see: www.rcseng.ac.uk/museums.

…a wagonette with a pair of cobs was waiting.
A wagonette, as its name implies, was an open wagon with side benchesÑrather more rustic than any conveyance Watson would have been used to in London. Cobs are sturdy draft horses, used for farm work.

…heavy with dripping moss and fleshy hart's-tongue ferns. Bronzing bracken and mottled bramble gleamed in the light of the sinking sun.
The parts of Devon not covered by the moors support lush vegetation. On the moors, an over-abundance of water soaking into the peaty soil creates the dangerous mires.

The moor is not as sinister as it appears in The Hound of the Baskervilles. At right, a pastoral scene on the moor includes grazing sheep and cattle, a hay wagon, and, in the foreground, some picnickers.