The volume of flame, however, is increased by inert gas, and there is a proportionate diminution of the heating effect. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 Various. Nitrogen by itself is an inert gas, colorless and uninflammable. Scientific American Supplement No. 819 Various.
There are two primary fungus diseases that can produce black spots on tomato plant leaves: Septoria leaf spot and Alternaria leaf spot, also known as early blight. Septoria and Alternaria differ slightly in appearance and prefer slightly different weather climates.
At first a yellow patch appears on the part of the tomato that is in hot, direct sunlight; when the fruit ripens, it forms a gray spot with a papery surface. This is not a reason to avoid full sun unless you live in a desert climate, where a little afternoon shade is okay.