This paper is the outcome of 12 months' private spectroscope building, two months' observing therewith, and ten months' computing and graphical presenting of the observations. The result is a Solar Spectrum map, extending through so many as 60 double quarto plates, but capable of being arranged for the cheapest photolithographic reproduction, in a manner very easy to examine, convenient for reference, and yet at the same time affording at every point new and severe tests for its degree of accuracy.