The onset of the Depression in the 1930s caused the matter to be raised once again, since it was felt that the project would provide much-needed work for the depressed building industry. Professor Sampson, Astronomer Royal for Scotland, was brought in as consultant. After examining several sites he came down strongly in favour of Balgay Hill as being by far the most suitable site, both in terms of astronomical suitability and for public access. This decision has stood the test of time, since other observatories have had their seeing conditions ruined by sodium lighting and other forms of modern pollution. The concept of a public observatory is, in a way, a contradiction in terms, since by definition, an observatory should be as far away from the public as possible. Most of the modern research observatories are situated on mountain-tops or desert areas. However, the geography of Dundee is unique, in that it has Balgay Hill overlooking a river estuary, protected from the main lights of the city by trees which also help to provide a purer atmosphere, and at the same time very accessible to the public. Something like 40% of all nights are observable.