The violet and ultra-violet regions of the spectra of the cool carbon stars are notoriously difficult to photograph. This is so particularly for the late N-type stars with which the present paper deals. The spectra of R-type and early N-type stars can be photographed down to ƛ3500 by exposures several times as long as for M-type stars of comparable class. However, the later N-type spectra fall so rapidly in intensity from ƛ4400 and so even more extremely from ƛ4100 to shorter wave-lengths that the spectra of the brightest stars have not been recorded below ƛ3900.