Getting Organized -22- 



standard fireworks type. (57) A fifth technique produced silver-iodide smokes 

 by first producing a silver smoke with an electric arc and then converting 

 the silver ^articles to silver iodide by the addition of iodine vapor to the 

 smoke. ( 56 ^ 



In addition to these, two other techniques were devised which were well 

 suited to large-scale seeding. In one, a solid fuel, such as charcoal, impreg- 

 nated with a silver-iodide solution, was burned. (57, 68) ^he silver iodide 

 vaporized and then condensed in the form of a fine smoke. In the other tech- 

 nique, a solution of silver iodide and acetone was atomized in a spray nozzle 

 and burned, vaporizing the silver iodide. (5 '>o8,73) fp^g silver-iodide vapor 

 rapidly condensed when it mixed with the cool air of the atmosphere, to form 

 a smoke of very small particles, the size of which could be varied over a wide 

 range. A later design of this generator, adapted for use in flight, was found 

 to be simple and reliable. 



Camera Clinometer, It became evident in early flights that it would be 

 necessary, when photographing seeded areas, to know the vertical angle at 

 which the camera was pointed. A very simple device was made (Langmuir- 

 Falconer) to attach to the camera to indicate this angle. (75) 



Flight Instruments . Standard instruments often had to be modified, 

 and new ones were occasionally developed. For example, a device was 

 evolved (Maynard-Falconer) to record the movement of the airplane "stick" 

 for correlation and measurement of vertical acceleration. (75) 



"Weather" Instruments. Eut it was in the field of weather observation 



and atmosphere studies that most of the instrument development occurred. Some 

 of the early devices were special rods (Falconer -Maynard) to be mounted on 

 the airplanes to determine the rate of icing;(75) an air decelerator (Schaefer- 

 Falconer) to assist in sorting out rain, snow, dust, or cloud particles from the 

 atmosphere as the plane passes through;(75>76) an( j a cloud-particle gun 

 (Schaefer -Falconer) for sampling the cloud -droplet size distribution in 

 clouds „('^ An attempt was made to develop a cloud-particle ranging instru- 

 ment for airplane use to provide a continuous record of the distribution of 

 particle sizes in a cloud, but without success. 



Cloud Meter . An important early development was a cloud meter 

 (Schaefer -Falconer), designed to provide information which would give a 

 measure of the average effective particle sizes in the various portions of a 

 cloud. ^ ' ' ' '' This device, embodying a continuously moving tape im- 

 pregnated with a water-sensitive dye, gave a satisfactory indication of the 

 amount of cloud particles collected. 



Condensation Nuclei Detector . Another important instrument (Vonnegut) 

 was one for obtaining a continuous record of the concentration of condensation 

 nuclei in a given air sample. (67) This involved a simple adaptation of the 



