An arithmatical amusement, said to have been first propounded in 1881, is the expression in the expression in the ordinary arithmatic and algebric notation of the consecutive integers from 1 upwards, as far as practicable, by the use of four “ 4 ”. I have mentioned the problem in my Mathematical Recreations, but my friend Mr. Oscar Eckenstein has now carried the solutions considerly further: I think a bare statement of our procedure may be of interest, and perhaps some readers ot the Gazette may amuse themselves by filling in the details ot the analysis or applying similar methods to higher numbers.

I wish to call attention to the value, for some purposes, ot the notation for the ratio ; and for the cross-ratio .

For instance: in Menelaus’ theorem for the property of a transversal meeting the sides of a triangle ABC in the points P, Q, R, the first mentioned notation makes the property shine out very clearly The equation in the form is

,

which conspicuously separates the points on the transversal from the angular points of the triangle.