Rösch. — We have already spent one third of the time available for this Symposium and I think it would be useful to say a few words about the present situation as I see it. We have had very lively discussions, but I am sure most of you have the feeling that there has been some confusion. This indicates that everyone is interested in the subject, but I hope that now we can restrict the discussion to better-defined fields. My feeling is that among all the factors involved that of turbulence is by far the most difficult. However we still have problems regarding the meteorological elements other than turbulence. I think it is excellent that the meteorologists here have been interested, although not always in agreement with the astronomers (but to disagree is much better than to have no ideas). What I would like to suggest now is that, before the end of this meeting, Dr. Dommanget have private discussions with the meteorologists about how we can use, for preparing site testing programmes, the data already collected by the meteorologists, and perhaps other data which they will give us in the course of their work. I hope that Dr. Dommanget can give us a 10-minute summary of these problems in one of the last sessions.