( 84) 



more tliaii Hann had derivLul f'ruin olKsoi'valious of' iiiomilaiii-slatioiis 

 and from those made by Glaisher. 



8'^'. Im])ortaiit dala have been acquired about the formation and 

 orighi of clouds, in coimection with tiie distribution of the meteoro- 

 logical elements. 



9''^ Tlie velocity of wind increases with the height, strongly 

 in the layers l)elow 1000 and above 3000 M, less so between these 

 two heights. At a height of 5000 M it was on an average 

 4.5 times as large as at the surface of the earth. Important data 

 w^ere also acquired about the difference in the direction of the wind 

 between the lower and higher parts of the atmosphere. 



10'''. Thermally and electrically the surface of a layer of clouds 

 has a similar effect uj)on the region above it as the surface of the earth. 



11'^' . The rate of decrease of electrical i)otential seems to diminish, 

 when rising, and even to \anish entirely in the higher regions of 

 the atmosphere. This result, arrived at from only few observations, 

 has afterwards been cori'oborated. 



It is not oidy the initiative in and the organisation, guidance, 

 partly also execution of, this interesting investigation, which are 

 mainly due to Assmann. We also owe to him the construction of the 

 aspiration-thermometer and -psychrometer, which has first rendered 

 possible trustworthy observations as to temperature and moisture 

 under the most different circumstances. It has a[)peai-ed that in 

 former balloon-expeditions (of Gi.aisher e.g.) errors to the extent of 

 even 15'^, owing to radiation, must have occurred in the indications 

 of the thermometers. 



Finally we ought to mention the introduction by Assmann of the 

 highly appropriate "Platz"-balloo]is made of caoutchouc, \n hich as 

 free registering-balloons can reach even a height of 20 to 30 kilo- 

 meters; there they burst and, provided with a i)arachute, return to 

 the earth very slowly with the instrument they convey. 



What is said above may be a sufficient reason for awarding the 

 medal to Assmann and Bkkson ; yet the committee cannot omit 

 referring to the excel lout work which is being done in the aero- 

 nautic observatory at Tegel near Berlin, founded by Assmann in 1899 

 and being directed by him. Here daily observations are made for the 

 examination of the u[iper air with the aid of kites, kite- and Platz- 

 balloons. The results are published daily and, since the beginning of 

 this year, as graphic reviews also monthly. 



If an examination of the higher layers of air can funiish many 

 important data more for our insight into the m3chanisni of atmos- 

 pheric phenomena — - which is hardly to be doubted — such a 



