An inquiry is made after the locus of lines with equal spatial distances of two, and the number of lines with equal spatial distances from three given lines. The results appear slightly different from those obtained by Bottema and Roth ( p. 51, Ex. 3, 4). In the sequel several special cases are considered which may be bypassed, marked with *. Explanatory remarks on some less-known mathematical concepts, marked with ¶, are given in the Appendix.