As Overland Mail's indebtedness to Wells Fargo climbed, Wells Fargo became increasingly disenchanted with Butterfield's management strategy. In March 1860, Wells Fargo threatened foreclosure. As a compromise, Butterfield resigned as president of Overland Mail, and control of the company passed to Wells Fargo.
It turns out that virtually no light with wavelengths longer than 690 nm is converted or captured by chlorophyll or carotenoids. Also, some light of shorter wavelengths than what humans can see is used by photosynthesis. Chlorophyll-a, chlorophyll-b and carotenoids all use light of wavelengths shorter than 390 nm. Interestingly, Chlorophyll-a can use light with wavelengths as short as 350 nm. This is getting into the UV or ultraviolet (above or beyond violet) range. For practical purposes, photosynthesis in general utilizes wavelengths of light from about 380 nm to 690 nm.
Concept 2: Electromagnetic Energy. The solar energy called visible light drives photosynthesis. Solar radiation is composed of electromagnetic energy that travels through space in a manner analogous to the motion of waves in water. The distance between the crests of waves is called the wavelength.