There's a common belief in the Chemtrail community that a Contrail can't persist for more than a minute or so, and that if it does that means it's a Chemtrail. Where does this idea come from? If you look at the internet, you see a lot of things like this, showing a short trail and a long trail, and saying the long trail is a Chemtrail and the short trail is a contrail. Now I'm not going to tell you one way or the other, because you've got no reason to trust me at some random guy on the internet. So let's have a look at what books on the weather say about the subject of contrail persistence. I'll start with the new books and go back to the older books so we can see if they're consistent. This is the book on cloud from 2002. Here's a picture of a contrail spreading out, and it says here contrail can evaporate rapidly or persist and grow into sheets of zero-form clouds. Peterson guide to the atmosphere. This is 1981. Here are some pictures of contrails, and it says sometimes they are femoral and dissipate as quickly as they form. Other times they persist and grow wide enough to cover a substantial portion of the sky with a seat of serostrotus. Clares of the world, 1972. More pictures of contrails. Once glaciated, glaciated means frozen. The trails may last for several hours and may be spread out by wind, sheer into almost horizontal sheets. Clouds and weather, 1969. And here they sometimes disappear quickly, but on other occasions they persist for a long time, spread out and become a serostrotocumulus type of cloud. Clouds start in color, 1967. And here's a picture of a whole bunch of contrails. And see, the cloud is then spread out by any wind, sheer, which may be present. And see, the cloud freezes almost instantly and does not readily evaporate. Color-glaed gate cloud, 1963. Here's a picture of some contrails. Contrals, sometimes the air is sufficiently dry for the ice cloud, so we have up to 10 minutes or so, but often it may last for several hours. Cloud study, a pictorial guide, 1957. Let me just show you that. First published, 1957. Here's a picture of some contrails spreading out. It's more wind-sheer can draw out a contrail into an almost horizontal sheet of cloud. Sometimes several trails draw out in this way, cover most of the sky with seroths, if the trails are very persistent. So there you have it. A range of books going back nearly 70 years. So who are you going to touch? Some guy on the internet? Or all the books on clouds for the last 70 years?