AbstractIt is a known fact that the accuracy of short bases measured in triangulation is soon lost in base extension nets. Additional degradation occurs as the net is extended, with the result that the scale error between two adjacent fixed stations may amount to 20 parts per million, which is much worse than what is expected from direct measurements with modern instruments. When subsidiary control is extended from the prjmary net by pure triangulation the error of the fixed scale will persist throughout the new network but a uniform scale error will not, by itself, cause figural distortions. If the new network is extended by trilateration or by“triangulateration”(a term used by Dixon [2]), figural distortions may become serious unless the conflict between the fixed scale and the scale of length measurelnents is identified and resolved. Dixon [2]deals with this problem by including a scale correction unknown in combined adjustments of angles and tellurometer lengths by the method of conditions. This paper discusses the fundamentals of the use of the scale unknown in adjustments by variation of coordinates and gives examples of the effect of fixed scale error on the adjusted results.