An inexpensive spectrograph using a concave diffraction-grating as a means of dispersing light has been designed. The grating and a slit were purchased; the rest of the instrument was constructed by semi-skilled labor. The spectrum is recorded on roll film at a cost for film of one cent or less per exposure. The instrument has been found suitable for qualitative and quantitative analysis of plant ash. Under favorable conditions the wavelength of lines can be detd. to [plus or minus] 0.4 A; the accuracy of quantitative detns. is comparable to that attained with prism instruments.