The reference is a general one, but the paintings of the Madonna by Giovanni Bellini mentioned by Ruskin in Modern Painters I are the Madonna in the Brera gallery ( MP I:84, and referred to again at Works, 12.285), and that in the church of San Franceso della Vigna in Venice ( MP I:84, and mentioned at Works, 11.379 as the reason for visiting that 'base Renaissance' building). Ruskin later refers to the paintings of the Madonna in the Frari and San Zaccharia churches in Venice as the two best pictures in the world (see Works, 24.363 and Works, 22.83), but neither is mentioned in Modern Painters I.
Giovanni Bellini c.1430-1516
Madonna and Child 1510
Oil on canvas, 85x118cm
Further Comments: Ruskin is unclear which Madonna he is referring to here, of which there are numerous. Also, on the web page given, the work is listed as c.1468, but according to Robertson and other sources, the canvas was signed IOANNES/BELLINVS/MDX, MDX being 1510ad.
Collection: Brera Gallery, Milan
For a reproduction of this artistic work, please consult: Robertson, Giles, Giovanni Bellini, (Oxford University Press, 1968), pl.107 or alternatively www.abcgallery.com/B/bellini/bellini65.html