In Beck's 1867 Catalogue, this instrument is described thus: "This Instrument may be placed either on a broad window-sill or on a table, and is intended for use at the sea-side, or where there is an extensive prospect. The Achromatic Object-glasses are 1 6/10inch in diameter, magnifying 15 linear ... The two wheels attached to one end of the Stand allow of a steady and easy horizontal movement; and the large milled head underneath ... gives a vertical one" (p. 6). The instrument also appears on p. 117 in Beck's 1881 Catalogue, perhaps indicating that lack of popularity meant that the old stocks were still being offered for sale 14 years later. It was certainly an expensive instrument: in 1867 it was priced at 14 pounds 14 shillings, which was the cost of an astronomical telescope with a focal length of 3 feet (92cm.) in the same catalogue (p. 8). This relatively high price could mean that few were sold, and account for the rarity of this piece.