The absence of flares in λ3835 and the heating of the chromosphere

Simultaneous observations of flares in H and a band 15 Å wide centered on 3835 Å show no change whatever in 3835 Å at the time of several flares, although the chromospheric network is easily visible. Flares are therefore transparent in this wavelength.Since the flare represents a test heat input from above, and no brightening of the network appears, we conclude it is impossible for the corona to produce the bright network by downward convection.