FWP:
SETS == BASKIH
WINE: {49,1}
WINE-HOUSE: {33,6}
For background see S. R. Faruqi's choices.
The second line juxtaposes a 'hair' on the 'glass, bottle' to a 'line' on the 'cup, bowl, goblet'. Are these two kinds of wine-vessels, the shiishah and the paimaanah , meant to be basically the same, or are we to take them as somehow contrasted? For more about Ghalib's various terms for wine-containers, see {28,1}.
A similar question arises about the relationship between the 'hair' and the 'line'. The 'hair' seems to be a 'hairline crack' in the glass; for another example of this usage, see {192,4}, which similarly features a muu-e shiishah , and even locates it at the same point in the verse.
But what about the 'line'? According to S. R. Faruqi (Aug. 2008), a line was commonly engraved into wine-glasses to mark the maximum level to which they should be filled; a well-bred person would never pour himself wine beyond the level of that line. Other examples of the same image: {28,1} a line on a jaam ; {33,2}, a line on an ayaa;G ; {199,1}, a line on a piyaalah . There's also {145,7x}, with a line on a miinaa ; though that is identified as 'the sacred-thread of the wine-flagon' and explained by Gyan Chand as an idiomatic way of describing the level of wine in a vessel that's half-full and half-empty.
Moreover, the two readings of baskih also yield piquantly opposite possibilities:
=although we're extremely drunk, we still clumsily try to do the elegant thing: we treat any old hairline crack in the wine-glass as though it were the 'line', and confusedly refrain from filling our glass beyond that level; perhaps we're even making that error of judgment on purpose, and pouring out less wine in order to help prevent ourselves from becoming any drunker
=we're so drunk, we're impaired to such an extent: that we actually confuse a random hairline crack in the wine-glass with the 'line' that should mark the limit of the wine-pouring
Gyan Chand rightly points out the wordplay: bishkan is related to shikan ('breaking, crushing, overthrowing, routing', Platts p.731), so that there's an enjoyable affinity with the 'hairline crack'.
Gyan Chand:
Because of the festivity of the wine-house, we are deeply intoxicated. Even if some 'hair' occurs in the bottle, we still don't care about it-- we consider it to be like the line that is inside the glass/cup, and ignore it. The dictionary meaning of bishkan is 'breaking'; the result of it will be the 'hair' of the glass. For there to be a line in the glass used to be the special quality of the Cup of Jamshed; now, it's brought in for every glass. (252)