lMass marketing of whiskey meant lots of competition between distilleries.  Consumers could buy hard liquor from their local Wine and Spirits Store or from their Grocer, but the quality was often highly suspect. 

(Click here for recipes used by rectifiers and blenders for making what was later sold as "rye whiskey" and "bourbon")  

The mail-order distillers had an advantage because their product was consistent and of high quality, but the sheer numbers plying their wares meant lots of competition.  Thus, the distillers used a number of inducements to persuade consumers to buy their particular brand and these came in the form of free clocks, plates, and even furniture!  The more common giveaways included smaller items such as corkscrews, trays, decanters -- and shot glasses.   The picture below is a good  example, taken from a 1902 Christmas flyer from Myers & Company of Kentucky:

"From this date until December 31, 1902, and not thereafter, we will present every purchaser with a handsome nickeled Tray, an engraved Decanter, a half-dozen Whiskey Glasses to match, and a patented key-lock polished brass spigot (which will last a lifetime) for each and every Cask order of 10 GALS."

The whiskey glasses mentioned and pictured  in the ad were probably one of the ones shown above.