The artist has concentrated on the tower itself, leaving the buildings which surround it completely blank.
The drawing shows the late-medieval Stadtturm in Baden (Switzerland), recognisable from its four corner-turrets, striped roof, and baroque clock and sundial faces. It appears to be shown from the south, looking along the Weite Gasse. Whilst Cook and Wedderburn describe the drawing as 'Probably by J.W. Bunney' (XXI.43 n. 5), a manuscript note to the drawing's entry in the Museum's copy of the catalogue to the Arts Council exhibition "Ruskin and his Circle" states that 'The artist's [i.e. Bunney's] grandson, however, believes it to be authentic.' Assuming it to be by Bunney, then it was presumably executed either in 1859 or in 1863, when Bunney was in Switzerland.
The drawing, along with all the other items numbered from 155 to 175 in the Reference Series, was never catalogued by Ruskin, appearing for the first time in Cook and Wedderburn's edition of the Drawing School catalogues as no. 173 in the Reference Series.
Ruskin himself visited Baden frequently, and several of his drawings made of Baden are recorded in Cook and Wedderburn's catalogue of his drawings (nos 151-159 = XXXVIII.230-1).
Presumably commissioned by John Ruskin and later presented to the Ruskin Drawing School (University of Oxford)
Ruskin, John, ‘The Ruskin Art Collection at Oxford: Catalogues, Notes and Instructions’, Edward T. Cook and Alexander Wedderburn, eds, The Works of John Ruskin: Library Edition, 39 (London: George Allen, 1903-1912), 21, cat. Reference no. 173