CHEMTRAILS = TRAILS CON -- TOTAL CRAP - debunked as phantasy
there is nothing to know.
... cirrocumulus cloud and a single spreading contrail,' he declared after inspecting one photo for a full minute. Then he flipped to the next. 'Nothing weird about that. Cirrostratus cloud...' And the next. 'The criss-cross pattern is a consequence of planes flying criss-cross patterns....' And the next. 'I've seen many situations like this one....' Contrail formation, Day explained, depends on the relative humidity of the atmosphere-- he ratio of what is to what could be at a particular temperature. When relative humidity is low, contrails dissipate within seconds. But when relative humidity is high, especially at the subzero temperatures of the upper atmosphere, the addition of even a tiny amount of water vapor acts as a catalyst. Under these conditions, contrails may linger and spread to cover the whole sky.
[He] extracted from his bookshelf a well-thumbed edition of Peterson's Field Guide to Clouds and Weather, which he co-authored in 1991 (a good 10 years before chemtrails became widely discussed), turned to the section on contrails, and pointed to a photograph of a thick, white plume--a plume that looked for all the world like a chemtrail..."
by Ian Williams Goddard
Since Environmental News Service published claims that military aircraft are spraying "contrails" that make people sick,  there has been an explosion of such claims. While there are known cases of military experimental spraying over American cities,  it was unclear to me whether these recent claims of a causal connection between contrails and illness are accurate or post hoc fallacies. 
The central premise of the claim that contrails are sprayed chemicals is that "normal contrails" dissipate within seconds. Therefore, contrails that persist or expand and blend with others into a haze are not mere water-vapor condensation but are instead composed of some kind of nonevaporating substance. I had the fortune to witnesses such contrail phenomena myself and took many photographs. It is my conclusion that what I observed seen in the following photos was the result of atmospheric conditions, and furthermore, I believe these phenomena may account for the majority of "spray-trail" reports I've heard.
Here are two composite images of four photographs I took:
Each side-by-side photo was taken within seconds of the other at one of two locations in Rockville Maryland, on February 11, 1999. It was an unusually warm day for February, reaching around 65 degrees Fahrenheit. While the surface air was dry, there was a haze starting several thousand feet above. All the contrails slowly spread out into this haze, exactly like accounts of "spray-trails" around the country. But I believe the contrails did not form the haze, rather, the humidity of a natural haze preserved the contrails.
This contrail proliferation appeared to have been caused by a bubble, or pocket, of dry and unusually warm air hugging the land above which there was very cold air. In an area between these two thermal regions -- an area containing a few thousand vertical feet of atmosphere -- condensation would naturally form. The high humidity in that area would naturally preserve contrails simply because nothing is evaporating in that area.
The next photograph taken on another day demonstrates that contrails hang and expand in a humid area and evaporate outside that area:
The photo shows three contrails persisting only within the clouds. The contrails had long-since evaporated in the area outside the clouds where they once existed. I observed this occur and predicted that it would as I watched the first jet approaching the clouds. This confirms to my satisfaction that natural humidity sustains contrails and that it is an error to assume that "normal" contrails do not hang and expand.
It might also appear that a fluffy substance is falling off an expanding contrail. Here's another photo I took on Feb. 11, notice that it could appear that the lower and most expanded contrail is dropping something fluffy (cobwebs?).
The structure of that fluffy "fall off" was consistent with a subtle natural fluffy texture appearing within the haze overhead. This photo shows a natural thin cloud structure intersecting with a large expanded contrail.
Notice the similarity of expanded-contrail structure and the natrual cloud structure. That fluffy structure manifested itself naturally in the haze layer. The contrails simply provided "grist for the mill," and as such, were inducted into the unique cloud-formation mechanics of that day. There was no epidemic of illness that I could detect after February 11, and these contrails were right over where I live.
 Environmental News Service: (a) Contrails Mystify, Sicken Americans. William Thomas, January 8, 1999. (b) Mystery Contrails May Be Modifying Weather. William Thomas, January 12, 1999.
 United States Senate Testimony: Open Air Testing with Simulated Biological and Chemical Warfare Agents. Leonard A. Cole, PhD, May 6, 1994.
 The post hoc ergo propter hoc fallacy
CONTRAIL ANALYSIS II
(c) Ian Williams Goddard
In my previous contrail analysis we observed that contrail persistence, or non-evaporation, is a function of relative humidity. However, the fallacy that contrail persistence is abnormal persists and is the primary basis of claims that persistent contrails are actually poison being sprayed on civilians by military jets. Since the military has sprayed experimental substances on U.S. populations in the past, claims to that effect deserve careful analysis. Such analysis reveals that contrail persistence is absolutely normal and is not evidence of spraying.
All the photographs below were taken by me on March 5, 1999. They show unique ice-cloud formations and provide further confirmation that contrail-persistance patterns are a function of natual atmospheric conditions. The first image captures what are known as fall streaks coming off a contrail.
A contrail is a linear cloud of condensation formed as hot air streaming from a jet engine mixes with cold air. Like a naturally occurring cloud of condensation, a contrail may evaporate or grow depending upon atmospheric conditions such as relative humidity.
The next photo taken while looking straight up shows a significantly expanded contrail running across the photo from which hair-like streams of crystallized condensation are being spread horizontally by the wind. This contrail with a "gray beard" is much older than the contrail running across the lower-left corner of the photo.
The following photographs reveal that naturally-occurring-condensation clouds also had a hair-like structure on that windy and cold winter day.
All these photographs show natural clouds not far from the contrails seen above.
Seeing an identical hair-like fall-streak structures in natural clouds verifies that the persistence patterns of the contrails in the first two photos are consistent with the effects natural atmospheric conditions were having that day on any frozen condensation, whether from a contrail or a natural cloud.
Ice content of the clouds was confirmed by frequent bright and slightly rainbow-colored solar reflections off them toward sunset. In the first photo of this pair, a solar reflection exists on a cloud in the upper right-side quadrant. In the second photo, a smaller solar reflection is visible just touching the left side of the large contrail.
Broken contrails: notice that the large persistent contrail in the first photo is broken. Some claim that a broken contrail means it's not condensation but a substance that was intermittently sprayed. Actually this phenomenon has been shown to be the result of the fact that the atmosphere is not a uniform medium, but is instead a turbulent patchwork of intermingling pockets, layers, and strata containing air with different temperatures, wind speeds, and levels of humidity. The contrail above initially existed in all locations but quickly dispersed only in those pockets of atmosphere the jet passed through that were not conducive to contrail persistence.
Different strata: notice that slightly above center in the second photo there is a new and fast-evaporating contrail that looks like a small comet. The jet was much higher than the thin cloud cover through which it is seen. Some argue that this phenomena means the persistent contrail seen below those clouds in the same photo must be spray, since another contrail "in the area" is evaporating.
That argument is only as plausible as the atmosphere is uniform, which it is not. The persistent contrail is near clouds in an area largely favorable to condensation. The evaporating contrail is in a higher and obviously drier atmospheric strata. In all these photos, there is only evidence of predictable atmospheric physics.
More identical structures: the following photo shows the fading remnants of a persistent and expanded contrail, which runs across the lower half of the photo:
Notice that the structure of the natural cloud formation above the expanded and fading contrail is basically identical to the structure of the contrail. In my previous contrail analysis we observed examples of similarities between contrails and surrounding natural clouds not only once but twice. In this analysis we have two more examples. So we have four examples in all of contrails being integrated into the natural cloud dynamics of the day.
CONCLUSION: both my previous contrail analysis and this follow-up present photographic verification that contrails do the same things that the natural clouds of condensation around them do; which demonstrates that what a contrail does -- whether it evaporates quickly or slowly expands into one of many patterns -- is a function of the natural atmospheric conditions in which it was formed. This is no new revelation, just as contrail persistence is neither a mysterious phenomenon nor evidence of spraying.