Langmuir's Claim
of a Seven-Day Periodicity
Caused by Cloud Seeding
Copyright 2002 by Ronald B. Standler
Introduction
In November/December 2002, while reading meteorology journals
from the early 1950s on cloud seeding, I came across an apparently
fantastic claim by Irving Langmuir that cloud seeding during 1949-51
had modified the weather more than 1000 kilometers downwind.
The specific project was conducted by Dr. Irving Langmuir's research
group (including Dr. Bernard Vonnegut)
at the General Electric Company, under contract to the U.S. Military.
As part of this project, Dr. Vonnegut released AgI from
a generator on the ground at Socorro, NM
on Tuesday, Wednesday, and Thursday of each week during
6 Nov 1949 to 27 April 1950.
(Langmuir's Collected Works, Vol. 11, p. 217)
Langmuir claimed that this release of AgI modified the weather,
not only in the state of New Mexico, but also
more than 1000 kilometers downwind.
Langmuir's evidence was a seven-day periodicity found in meteorological
records in the Ohio River Valley,
the Wabash River Valley,
as well as in New England.
Annotated Bibliography
Langmuir made a few public presentations of his claims at meetings
of various scientific societies, and brief versions of his claims
were published at:
- Irving Langmuir, "Control of Precipitation from Cumulus Clouds
by Various Seeding Techniques," Science, Vol. 112
pp. 35-41, 14 July 1950. (Focuses on rainfall
in New Mexico, but tersely mentions rain in Kansas "may"
have been caused by AgI seeding in New Mexico.)
- Irving Langmuir, "Widespread Modification of Synoptic Weather Conditions
by Localized Silver Iodide Seeding," Science, Vol. 112
p. 456, 20 October 1950. (Expands claim to Kansas,
and says: "significantly high correlations between
times of rainfall and the times of the systematic seedings up to
2000 miles [3000 km] downwind from the point of seeding.")
- Irving Langmuir, "A Seven-Day Periodicity in Weather in United States During April, 1950,"
Bulletin of the American Meteorological Society, Vol. 31,
pp. 386-387, December 1950. (Claims that periodic AgI release in
New Mexico caused a corresponding periodicity in "pressure,
humidities, cloudiness, and temperature over much of the United States",
including Chicago and Buffalo, NY.)
Criticism of Langmuir's Claims
Langmuir's claims were rejected by the meteorological community,
because Langmuir's published evidence was inadequate.
The following is a partial list of publications that disagree with
Langmuir's claims:
- Ferguson Hall, Comments and Communications: "Dr. Langmuir's
Article on Precipitation Control," Science, Vol. 113
pp. 189-191, 16 February 1951.
(Refutes Langmuir's July 1950 paper, principally because
Langmuir incorrectly assumed that precipitation in adjacent grids
on a map are independent events, and because the wind could not
have carried the AgI smoke to all of the areas where Langmuir
claimed rain had fallen as a result of the cloud seeding.)
- G. Emmons, B. Haurwitz, G.P. Wadsworth, and H.C. Willett,
Comments and Communications: "Dr. Langmuir's
Article on Precipitation Control," Science, Vol. 113
pp. 191-192, 16 February 1951.
(Calls Langmuir's October 1950 claim of modified rainfall in
the Mississippi Valley "fantastic", and says that Langmuir's
published statements are inadequate to allow verification of his claim.)
- William Lewis, "On a Seven-Day Periodicity,"
Bulletin of the American Meteorological Society, Vol. 32,
p. 192, May 1951. (Finds seven-day periodicity in weather
in two out of five years during 1938-42; such periodicities not caused
by cloud seeding.)
- Eberhard Wahl, "Seven-Day Periodicity in Weather in the United States During April, 1950,"
Bulletin of the American Meteorological Society, Vol. 32,
p. 193, May 1951. (Finds seven-day periodicity in weather
at Boston in April 1879 and also in Mitchel Field, NY
in April 1947; such periodicities not caused by cloud seeding.)
- H.F. Hawkins, Jr., "The Weather and Circulation of May 1952,"
Monthly Weather Review, Vol. 80,
pp. 82-87, May 1952. (Finds seven-day periodicity in weather
in May 1952, after Vonnegut's AgI release has been discontinued.)
- G.W. Brier, "7-Day Periodicities in May, 1952,"
Bulletin of the American Meteorological Society, Vol. 35,
pp. 118-121, March 1954.
(Confirms Hawkins' seven-day periodicity in weather in May 1952,
after Vonnegut's AgI release has been discontinued, but notes that
Langmuir claims that commercial cloud seeders on the West Coast
of the USA were then releasing AgI with a weekly periodicity.
Brier suggests that naturally occurring seven-day periodicity of
the weather was influencing commercial cloud seeders choice of
when to release AgI.)
- G.W. Brier, "Seven-Day Periodicities in Certain Meteorological Parameters During the Period 1899-1951,"
Bulletin of the American Meteorological Society, Vol. 36,
pp. 265-277, June 1955.
(This article "was prepared in late 1952" but publication was delayed
for three years for unspecified reasons. Also strangely, the article
explicitly declares its scope as only to "report the facts" and
neither to evaluate Langmuir's evidence nor interpret the facts.
Reading between the lines, it is possible that the U.S. Weather Bureau,
who employed Brier, had censored Brier.)
Langmuir's Reaction
Instead of publish adequate evidence,
Langmuir appears to have ceased publishing in journals of professional
scientific societies. I can think of two reasons for this sudden
cessation of publications by Langmuir:
- Perhaps Langmuir was annoyed by the harsh criticism by meteorologists.
- Perhaps Langmuir was censored by managers and attorneys for General Electric
Company who were trying to avoid tort liability for flooding
near Kansas City in July 1951. Langmuir had earlier
said that AgI release by Vonnegut in New Mexico
had caused rain in Kansas, and General Electric was releasing AgI in
New Mexico during June and July 1951.
Of these two reasons, the second appears more likely to me.
Vonnegut, who was a prolific author of scientific papers, apparently never
published any discussion of why he chose a weekly periodic
release of AgI, and apparently never published any discussion of the
results of his periodic release. Given General Electric's careful assignment
of all cloud seeding from airplanes to the U.S. Military
(i.e., with General Electric's employees only as observers),
Vonnegut's release of AgI smoke from the ground seems to me to have
violated General Electric's policy of having only the U.S. Military
make decisions when and where to release AgI.
Langmuir's detailed evidence was given in a tediously long technical report
issued by General Electric company as part of the research project
sponsored by the U.S. Military. (Final Report of Project
Cirrus, Part II, General Electric Research Laboratory Report RL-785,
May 1953.)
This report was initially classified by the U.S. Military,
but later declassified and published in 1961 in
The Collected Works of Irving Langmuir, volume 11.
The important thing to note here is that Langmuir's critics (with the possible
exception of Brier) probably had not seen the then classified report.
Conclusion
My opinion is that there was a naturally occurring seven-day periodicity
in the weather in the central and eastern USA at that time, and it is purely
coincidence that Vonnegut operated his AgI generator on a weekly cycle.
Further, Langmuir never publicly published adequate evidence for his conclusions
that (1) AgI release caused rainfall far from the point of release
or (2) periodic AgI release caused periodicities in meteorological
variables.
Langmuir's controversial and fantastic claims are now only
a small detail in the history of science and technology, which is why
I have written about them in a separate essay from my other essays on the
law and
technology of weather modification.
If one were interested in evaluating the long-range effects of AgI release,
it would be better to do a new experiment than to re-examine Langmuir's old data.
A new experiment could take advantage of modern technology, including
use of tracers (e.g., SF6) to follow the AgI in the atmosphere.
Prof. Byers made the following tantalizing remark:
- One has only to ask that someone in the Southwest [USA] repeat
this ridiculously simple experiment to see what vindication can
be found for Langmuir.
- Horace R. Byers, foreword to The Collected Works of Irving Langmuir,
volume 11, p. xx, 1961.
this document is at http://www.rbs2.com/w3.htm
revised 23 Dec 2002
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