[…] an idle extravagance which was mistaken for elegant luxury — tumble-down old hackney-coaches, such as had not been seen north of the Potomac for half a century, harness never cleaned, undergroomed horses […]

A Pommie. They were sending him to England to work with a Pommie. After all that he had done for this country they were shipping him off to a cold, rain-infested, windy little isle to work a case with a Pommie.

a two-handed game of cards

Measure the depth of the water in this part of the bay.