DR. MAX COSYNS is to be warmly congratulated on his successful ascent into the stratosphere on August 18. The disaster of the two previous ascents had not deterred the chief actors in this from going forward with their prepara tions, for it will be remembered that the American ascent came to grief only so recently as July 28. Dr. Cosyns was accompanied on this ascent by M. van der Elst, and the project was under the auspices of the Belgian Fonds National de la Recherche Scientifique which gave the balloon its name F.N.R.S. It had a capacity of about 14,000 cu. metres and was provided with an aluminium gondola with special means of rapid exit. The motive of the flight was the investigation of the directive tendency of the cosmic radiation, and as a good landing has been made it is to be hoped that the records are safe. The ascent was made from Hour-Havenne in the valley of the Lesse in Belgian Luxembourg at 6.10 a.m. on Saturday in perfect weather conditions, and the descent at Zenavlje in Yugoslavia at 9.30 p.m. on the same day. The height reached, as reported in the daily newspapers, was about 10 miles. Though this does not constitute a record for height, the recent aeroplane work of Blackett and Gilbert in Great Britain at comparatively low altitudes shows the value of such data as may be obtained in this manner in resolving the problem of the directive tendency of the cosmic radiation. A further point of interest is the fact that the balloon covered a distance of about 1,000 miles in a general south easterly direction during a period of 15 hours. This would indicate a very high wind velocity at high altitudes.