100 YEARS AGO

The remarkable subsidences which have often occurred in and around the town of Northwich, in Cheshire, form the subject of a paper by Mr. T. Ward, recently issued by the Institution of Mining Engineers. The subsidences are chiefly due to mining in the Upper Bed of rock-salt, and the too rapid removal of brine by means of modern pumps. In a natural condition the water in or on the salt-beds becomes saturated with salt and then ceases to dissolve it, but now the brine is continually pumped up in immense quantities, and the fresh water which flows to take its place dissolves the salt pillars which have supported the roof and overlying strata, with the result that there is a depression towards each pumping centre. In almost every case the mines in the Upper Bed of rock-salt are destroyed by water rapidly eroding the salt pillars in this way. Another cause of subsidence is the pumping of brine from off the rock-head, that is, the surface of the Upper Bed of rock-salt. . . By degrees the town is becoming one of framework buildings, and will, for England, be unique in this respect. The accompanying illustration, which we are enabled to give from Mr. Ward's paper, shows a subsiding house in a street at Northwich.

From Nature 28 March 1901.

50 YEARS AGO

John Constable's Clouds. This is more of a philosophical than a meteorological treatise. The author is mainly concerned to demonstrate the influence upon John Constable and, incidentally, also upon Goethe, of Luke Howard's system of cloud classification. There have been other great cloud painters such as Turner and Ruisdael; but Constable's work rests on a knowledge of Howard's system and it is this which makes the dynamical quality of his cloud studies, so suggestive of rapid change, highly interesting to meteorologists. This is surely a striking example of the aid which science can render art. . .

From Nature 31 March 1951.