Since Environmental News Service published accounts on jets spraying "contrails" that make people sick, I have seen an explosion of such accounts. While there has been a track record of military experimental spraying over U.S. cities, it is unclear to me whether the recent widespread claims of a correlation between contrails and sickness are accurate or are perhaps a post hoc ergo propter hoc fallacy (http://assiniboinec.mb.ca/user/downes/fallacy/posthoc.htm).
After getting reports of unusual contrail formations in my area, I went out and observed and photographed a surprising proliferation of contrails. I've concluded that attributes assumed to indicate a contrail is spray are attributes of normal contrails under variable atmospheric conditions.
I took many photographs, some of which provide proof that assumed-to-be-abnormal attributes of contrails are normal, and as such are not evidence of spraying. See my analysis with photos: http://www.erols.com/igoddard/contrail.htm
Accounts that my observations do not address are those of "cobwebs," "angel hair," or a gel-like substance falling. There was one inexplicable contrail that I photographed.
GODDARD'S JOURNAL --> http://erols.com/igoddard/journal.htm