294 THE FUTURE OF ARID LANDS 
Conclusions 
The results above suggest immediately several experiments in 
silver iodide seeding which might be of outstanding importance 
in the whole problem of weather modification. 
1. Silver iodide seeding from aircraft operating at moderate or 
at high altitudes. Under these conditions the decay rate of the 
silver iodide might be low and the material is already at approxi- 
mately the height where it can become effective in clouds. 
2. A seeding experiment in which silver iodide is dispensed 
from a high mountain peak where the ambient temperature is 
near or below o°C. 
The results also bring out the importance, in any experiments 
of this kind, of independent measurements being made to verify: 
lO-Ka + 
N N 
NS SS Ss 
go EON 
w~ NN ‘ 
Ne N SS XS 
560 N SS 
+ NX \ 
19) e aN N+ 
(e 
a SN 
SOMES 
5 Ra 
AACE S < N 
6 S NeETTES 
t oy 
s e\A, + 
E NEN 
< \ 
20 x 
N 
aN 
» Ne 
re XS 
L a ft n sui tee 
O3 Ke) 3 10 30 100 300 
Time for a decay to one-tenth concentration (mins) at 
atmespheric pressure 
Figure 3. The decay in activity of silver iodide particles as a function 
of air temperature. 
