At the outset some attempt at classification is desirable. We may refer the reader to the very exhaustive list of varieties which that great authority, Mr. Albert Hartshorne, has made in his standard work on this subject. For our purpose it will be sufficient, however, to make a broad and simple division of drinking glasses into wine glasses, ale and beer glasses, and cordial or spirit glasses. It is the custom, too, to draw a distinction between the rude vessels made for common household or tavern use and the finer and more highly finished examples designed for the use of better-class people. Here, however, the distinction is rather one of quality than of kind. The three great groups to which we have referred fall into various classes according to the diversity of shape in bowl and stem and, to a less degree, of foot. The bowls are variously funnel-shaped, with straight sides, or waisted, that is, with the sides curved inward to form a waist, bell-shaped, and ogee or double-ogee shaped--the last named showing in section the ogee curve, so widely employed by the architect for his mouldings. The stems are of two great classes--drawn stems or stuck stems. The former are parts of the same lump of molten glass of which the bowl is formed; the latter consist of a separate piece fused into the bowl. As regards shape, stems may be plain rods, rods with knops, rib-twisted, faceted, air-twisted, air-drawn, or opaque-twisted. We shall deal with each variety in its appropriate place. With regard to the foot, the generality were folded, that is to say, the edge of the rim was turned under to form a fold or welt, so that the glass stands on the rim, and not on the flat of the foot. Apart from this, the only variations are those bearing on the flatness of the foot and its diameter. In old glasses the feet were never quite flat. There is always a perceptible slope from the centre to the rim, and very often the central portion rose up into a dome. The foot was also wider in comparison with the width of the bowl than in the modern type.