An improvement on the above useful appendage to a merchant's counting-house has been invented by J. N. Ayres, of Stamford, Conn., who has taken measures to secure a patent. For this purpose, instead of the ordinary1 method of arrangement by which separate cards are required every day and month, the inventor employs three endless bands, with the days ol the week, dates of the month, and months of the year, printed on their front sides. These bands pass over rollers inside a box, and are made to appear successively as the rollers are turned through slots or apertures, by which they are brougnt to view, and as a protection from injury there is placed in front a piece of glass, or some other transparent substance through which they can be read off.