t amuses me enormously to paint the night right on the spot, " wrote Vincent van Gogh to his brother Theo. " Normally, one draws and paints the painting during the daytime after the sketch. But I like to paint the thing immediately. It is true that in the darkness I can take a blue for a green, a blue lilac for a pink lilac, since it is hard to distinguish the quality of the tone. But it is the...

Discrete autocorrelation (a.c.) wavelets have recently been applied in the statistical analysis of locally stationary time series for local spectral modelling and estimation. This article proposes a fast recursive construction of the inner product matrix of discrete a.c. wavelets which is required by the statistical analysis. The recursion connects neighbouring elements on diagonals of the inne...

Communications relative to advertising should be addressed to THEO. J. CHRISTENSEN, 1515 Massachusetts Avenue, N.W., Washington 5, D. C. Communications relative to membership in the Association and to all matters of business of the Association should be addressed to the Administrative Secretary, AAAS, 1515 Massachusetts Avenue, N.W., Washington 5, D. C. Annual subscription, $7.50 Single copies,...