Seems like I've stumbled onto this thread a few years late, but if anybody's interested "Soldier's Joy" in the 18th Century probably referred to spruce beer rather than the mid-19th Century association with morphine. In the British Army each soldier was entitled to about a half gill of rum per day. The catch was, there was an "off reckoning" from the soldier's meagre pay to cover it's cost (as there was for much of his uniform beyond the basic forst issue upon recruitment). Should the soldier's in any given army allow the issue of locally brewed spruce beer in place of the rum ration, there would be no "off-reckoning" for it, and so it is believed to be the source of the phrase "soldier's joy". I've actually found among the names on the Cambridge Parole (which lists Gen. Burgoyne principle officers, aides, and staff after they surrendered at Saratoga in Oct. of 1777), a guy named Powell, who was listed as "asst. commissary of beer", and another guy named McKenzie, with the even more arcane title of "deputy asst. commissary of beer". The actual Commissary of Beer was in Montreal and Powell and McKenzie were detailed to brew spruce beer in the immediate rear of Burgoyne's Army as it worked it's way down from Canada in their failed attempt to take Albany.