p. ??. “the four points A, C, D, B are concylic” in original, evidently intended is “concyclic”. p. ??. as p. ??. p. ??. “Through tho point E” in original, obvious error amended to “the”. p. ??., p. ??. “the points A, B, C, D are concylic” in original, as p. ??. p. ??. “(Ex. 2.) …or touchlng a given file and a given circle.” in original, obvious error amended to “touching”. p. ??. “21. What is the locus of the middle points …” in original, amended to “31.” in sequence. p. ??. In (21) “the if then line DE intersect the chords …” in original, garbled phrase amended to “then if the”. p. ??. In (44) “these circle sintersect” in original, misplaced space amended to “these circles intersect”. p. ??. “4. The point of bisection (1) of the line (OP)” in original, from the diagram and following discussion this should be (I). p. ??. Prop. IX. “About a given circle (ABCD) to describe a circle.” in original, clearly this is nonsense and must mean “About a given square”. p. ??. “Then the traingles ABO, CBO” in original, obvious error amended to “triangles”. p. ??. In (52) “and also en equilateral circumscribed polygon” in original, wrong letter amended to “an”. p. ??. Heading “PROP. XXV.—Problem.” in original, the preamble to this book says that every Proposition in it is a Theorem and this one seems to be no exception, so amended. p. ??. Reference “[I.]” is to Proposition I. of current book, amended to “[i.]” (4 times). p. ?? sqq. Reference “[II.]” is to Proposition II. of current book, amended to “[ii.]” (4 times). p. ??. Prop V. header “subtended bg the homologous sides” in original, obvious error amended to “by”. p. ??. Reference “[XVI.]” corrected to “[xvi.]”. p. ??. “From the construction is is evident …” in original, obvious error amended to “it is”. p. ??. “20. Find a poiat O” in original, obvious error amended to “point”. p. ??. “the lines GH, GK each perpendiclar to EF” in original, obvious error amended to “perpendicular”. p. ??. “O” when associated with a lower case letter was wrongly printed as o, which is not defined. These have been corrected (3 times). p. ??. Reference “[VI., Cor. 6]” corrected to “[vi., Cor. 6]”.