"It is a great defect in most school courses of geometry that they are entirely confined to two dimensions. Even if solid geometry in the usual sense is not attempted, every occasion should be taken to liberate boys' minds from what becomes the tyranny of paper... But beyond this it should be possible, if the earlier stages of the plane geometry work are rapidly and effectively dealt with as here suggested, to find time for a short course of solid geometry. Euclid's eleventh book is generally found dull and difficult, but all that is of real value in it can be dealt with much more rapidly, especially if full use is made of the idea of the motion of a line or of a plane. Similarly it should be found possible to include a study of the solid figures; this will be much facilitated if their general outlmes have been made familiar at the very commencement as is usually the case."
Board of Education Circular on the teaching of Geometry (No. 711, March 1909).
It may be argued that the course of plane geometry gives all the practice necessary in the use of formal logic as applied to mathematics, that the course in solid geometry should not aim at giving further practice in formal logic, but rather at imparting the power of 'thinking in space.' Whether this argument is sound or not, it is generally found in actual practice that the choice lies between informal solid geometry and no solid geometry at all: there is no time for a course on the lines of Euclid XI.