With marginal numbers and measuring tape attachment for instantly locating points of interest within a radius of twenty miles from the Capitol / by Axel Silversparre, C.E. CREATED/PUBLISHED Washington : R.E. Whitman, c1887. NOTES Covers part of D.C., not 'a radius of twenty miles from the Capitol.' Depths shown by soundings. Includes inset, sector diagram, and source materials notes.