HI ,
Just to clarify , 18th c deceptive glasses don't have shallow bowls they have bowls with very thick walls which taper down to the base of the bowl,the idea is that the glass looks like a normal capacity wine or dram glass but actually holds far less than a normal 1 ,so the Toastmaster appears to be having his share , but stays fairly sober , it is recorded that some toasting sessions could amount to several dozen toasts at 1 sitting
cheers,
Peter.