1230 
measurements; and third, that simplified dependable 
instruments are seriously needed both for routine use 
and for specialized research programs. Improvement 
in this field of endeavor might be accelerated by a more 
integrated approach, closer coordination among those 
working in the field, and more unified objectives. It is 
time, for example, to consider a ‘‘one-piece”’ instrument 
which would record a number of the quantities we have 
discussed above. The military aerograph AN/AMQ-2 
[29, 47] was a step in that direction, but it records only 
temperature and humidity (with serious lag), pressure 
altitude, and air speed. In a unified instrument many 
of the quantities could be reduced to the same type of 
measurement—a temperature or a pressure measure- 
ment, for example—and all quantities might be re- 
corded coincidently on a single chart or magnetic tape. 
It is clear that advancement requires both sound en- 
gineering applied to known techniques, and able scien- 
tific attack where techniques are now adequate. 
In addition to much helpful advice from many co- 
workers in this general field, I wish especially to ac- 
knowledge the constructive criticism of Robert M. 
Cunningham who has been actively associated with 
the development of aircraft meteorological instruments 
since 1942, and to recognize the able assistance of Mrs. 
B. A. Wallace in the preparation of the manuscript. 
REFERENCES 
1. Barrett, EH. W., and Suomt, V. E., ‘‘ Preliminary Report on 
Temperature Measurement by Sonic Means.”’ J. Meteor., 
6: 273-276 (1949). 
2. BuancHarD, D. C., The Use of Sooted Screens for Determin- 
ing Raindrop Size and Distribution. General Electric 
Res. Lab. Occasional Rep. No. 16, Project Cirrus, Con- 
tract No. W-36-039-sc-38141, Schenectady, N. Y., Nov. 
1949. 
3. Brewer, A. W., Cwitone, B., and Dosson, G. M. B., 
“Measurement of Absolute Humidity in Extremely Dry 
Air.” Proc. phys. Soc. Lond., 60: 52-70 (1948). 
4. Brock, G: W., “‘Liquid-Water Content and Droplet Size 
in Clouds of the Atmosphere.” Trans. Amer. Soc. mech. 
Engrs., 69: 769-770 (1947). 
5. Byars, H. R., and Branam, R. R., Jr., The Thunderstorm. 
Washington, D. C., Supt. of Documents, 1949. 
6. CasHman, R. J., ‘“New Photo-Conductive Cells.” J. opt. 
Soc. Amer., 36: 356 (1946). 
7. CunnineHam, R. M., and Mitier, R. W., Five Weather 
Radar Flights: Measurement and Analysis. Mass. Inst. 
Tech. Signal Corps Contract No. W-36-039-sc-32038, 
Tech. Rep. No. 7, Cambridge, Dec. 1, 1948. 
8. Diem, M., ‘““Messung der Grésse von Wolken-Elementen.”’ 
Ann. Hydrogr., Berl., 70:142-150 (1942). 
9. Done ty, P., ‘‘SSummary of Information Relating to Gust 
Loads on Airplanes.”’ Tech. Notes nat. adv. Comm. Aero., 
Wash., No. 1976 (1949). 
10. Drestos, H. C., Instrumentation of a B-17 Aircraft for 
Weather Radar Flights. Mass. Inst. Tech. Signal Corps 
Contract No. W-86-039-sc-32038, Tech. Rep. No. 10, 
Cambridge, March 1, 1950. 
11. Extiorr, H. W., Cloud Droplet Camera. National Res. Lab. 
Rep. No. M.1.-701, National Research Council, Ottawa, 
Canada, Dec. 1947. 
12. Fatconer, R. E., and Scuarrer, V. J., A New Plane Model 
13. 
14. 
25. 
26. 
27. 
28. 
29. 
30. 
31. 
32. 
33. 
METEOROLOGICAL INSTRUMENTS 
Cloud Meter. General Electric Res. Lab. Occasional Rep. 
No. 2, Project Cirrus, Contract No. W-36-039-sc-32427, 
Schenectady, N. Y., May 1948. 
Fostsr, N. B., and Fosxert, L. W., ‘‘A Spectrophotometer 
for the Determination of the Water Vapor in a Vertical 
Column of the Atmosphere.” J. opt. Soc. Amer., 35: 601— 
610 (1945). 
Friswo1p, F. A., Lewis, R. D., and WHEEter, R. C., ‘‘An 
Improved Continuous-Indicating Dew-Point Meter.’ 
Tech. Notes nat. adv. Comm. Aero., Wash., No. 1215 (1947). 
Gunn, R., Preliminary Report of the Measurement of the 
Size and Distribution of Raindrops. Naval Res. Lab. 
Tech. Rep. No. A767A, Washington, D. C., Oct. 4, 1944. 
. — “The Electrical Charge on Precipitation at Various 
Altitudes and Its Relation to Thunderstorms.” Phys. 
Rev., 71: 181-186 (1947). 
. — “‘Hlectric Field Intensity inside of Natural Clouds.”’ 
J. appl. Phys., 19: 481-484 (1948). 
. Guyton, A. C., “Electronic Counting and Size Determina- 
tion of Particles in Aerosols.” J. industr. Hyg. Toz., 
28: 183-141 (1946). 
. Hamermess, B., Rernus, F., and Korrr, 8. A., ‘‘A Photo- 
electric Hygrometer.”’ Tech. Notes nat. adv. Comm. Aero., 
Wash., No. 980 (1945). 
. Harrison, G. R., Lorp, R. C., and Loorsourow, J. R., 
Practical Spectroscopy. New York, Prentice-Hall, Inc., 
1948. (See pp. 300-325) 
. Hizron, W. F., “Thermal Effects on Bodies in an Air 
Stream.’’ Proc. roy. Soc., (A) 168: 43-56 (1938). 
. Hoveuton, H. G., ‘On the Relation Between Visibility 
and the Constitution of Clouds and Fog.” J. aero. Scz., 
6: 408-411 (1939). 
. — and Bemis, A. C., ‘‘Cloud Particle Studies on Mt. 
Washington.” Bull. Amer. meteor. Soc., 20: 400-401 (1939). 
. Houeuton, H. G., and CHatker, W. R., ‘‘The Scattering 
Cross Section of Water Drops in Air for Visible Light.” 
J. opt. Soc. Amer., 39: 955-957 (1949). 
Hoveuton, H. G., and Raprorp, W. H., “‘On the Measure- 
ment of Drop Size and Liquid Water Content in Fogs 
and Clouds.’’ Pap. phys. Ocean. Meteor. Mass. Inst. Tech. 
Woods Hole ocean. Instn., Vol. 6, No. 4 (1988). 
Humpureys, W. J., Physics of the Air. New York, McGraw, 
1929. (See pp. 433-555) 
Jonss, A. R., and Luwis, W., A Review of Instruments De- 
veloped for the Measurement of the Meteorological Factors 
Conducive to Aircraft Icing. N.A.C.A. Res. Mem. No. 
A9CO9, Washington, D. C., April 1949. 
Kamps, H. J. aufm, “Visibility and Liquid Water Content 
in Clouds in the Free Atmosphere.” J. Meteor., 7: 54-57 
(1950). 
Ketny, D. P., Meteorological Instrumentation for All- 
Weather Operations Section. Air Tech. Service Command, 
U.S. A. F., Wright Field, Dayton, Ohio, Oct. 1945. 
Kouter, H., ‘““Wolkenuntersuchungen auf dem Sonnblick 
im Herbst 1928.”’ Meteor. Z., 46: 409-420 (1929). 
Lanemutir, I., and Broperrt, K. B., A Mathematical In- 
vestigation of Water Droplet Trajectories. General Electric 
Res. Lab. Rep., Contract W-33-038-ac-9151, Schenectady, 
N. Y., July 1945. 
Lewis, W., and Horcxrr, W. H., ‘Observations of Icing 
Conditions Encountered in Flight during 1948.” Tech. 
Notes nat. adv. Comm. Aero., Wash., No. 1904 (1949). 
Matxus, W. V. R., BisHop, R. H., and Briaas, R. O., 
“Analysis and Preliminary Design of an Optical Instru- 
ment for the Measurement of Drop Size and Free-Water 
Content of Clouds.” Tech. Notes nat. adv. Comm. Aero., 
Wash., No. 1622 (1948). 
