WRITING in reference to our leading article on “Inland Water Survey” in the issue of NATURE of October 27, Mr. Alan Chorlton, M.P., says that while generally supporting the project for the institu tion of a survey at an early date, he considers there are other factors which should be taken into account. To arrive at the total of the water supplies of Great Britain without proper relation to where they are likely to be called for would be, he fears, to create another break in the development of water supply in the country. He alludes to an air survey for the positioning of aerodromes and notes that town and country planning call for something to be done to bring the Ordnance Survey up to date. It seems to him that consideration should be given to the general interrelation of all these matters in order to ensure that they will ultimately be properly co-ordinated. “A water survey should, at least, be undertaken with relation to the areas the water is required for: that is, a combination of survey with the recom mended allocation”.