MR. HARDING'S letter (NATURE, January 25, p. 414) reminds me of an experience which, in view of the rarity of the phenomenon, may be of sufficient interest to place upon record in these columns, although the newspapers of the period the sixties of last century—duly noted the occurrence. It must, I think, have been in 1866 or 1867 (date and year uncertain) that I had occasion to go from the West to the East End of London. Starting upon my journey about 10 p.m., it began to rain soon after I left the house in Bayswater, and I opened an umbrella, which, to my surprise, became stiffer and heavier every moment, and was found on examination to be so thickly glazed over with ice that it was impossible to close it. At the same time the pavements and roadway were also becoming uniformly glazed; pedestrian movement was most difficult, and all horse traffic was suspended. Although an experience of some forty-five years ago, the impression left upon my memory is still vivid— the ludicrous sight of people carrying ponderous and rigidly frozen umbrellas which they could not close, the stream of skaters down Oxford Street and Holborn, and the silence due to the absence of vehicles, all came to mind on reading Mr. Harding's letter. It took me on that occasion more than four hours to perform a journey of about two miles, and progression was only made possible by encasing my boots in the folds of a woollen scarf which I was wearing at the time, which I took off and cut into two portions for the purpose. There was no viaduct at that time, and Holborn Hill interposed serious difficulties.