Cirrus and Stratus Studies -37- 



The conclusion was therefore reached in the earliest days of the pro- 

 ject that cloud seeding could produce holes in stratus clouds. Thus a plane 

 should be able to clear a hole for itself. The result would be not only to 

 increase visibility but also to eliminate icing conditions. 



Langmuir made an exhaustive analysis of the photographic data ob- 

 tained on these early test flights, reaching some very interesting conclu- 

 sions regarding the nature and behavior of stratus clouds/ *> 



It was soon found that a very useful technique in seeding stratus 

 clouds was to seed in patterns--L shapes, race-track shapes, Greek gam- 

 mas, etc. Thus it would be possible to watch for modification of the clouds 

 following the same pattern. And invariably modification did occur, agreeing 

 with the pattern of the seeding. In many cases clear areas were produced 

 in the cloud deck. 



Among the stratus cloud studies made by the project were: 



(1) The effect of seeding supercooled stratus clouds with 

 various amounts of dry ice and silver iodide. 



(2) The optimum quantity of seeding agent required to pro- 

 duce large cleared areas in an otherwise solid deck of 

 supercooled clouds. 



