Without further explanation he pushed the scales toward the next door. The following day I noticed that the portions of food served me were a trifle smaller than they had been previously. The original Karl Armstadt had evidently been of such build that he carried slightly less weight than I, which fact now condemned me to this light diet. However, I reasoned that a light diet is conducive to good brain work, and as I later learned, the object of this systematic weight control was not alone to save food but to increase mental efficiency, for a fat man is phlegmatic and a lean one too excitable for the best mental output. It would also help my disguise by keeping me the exact weight and build of the original Karl Armstadt. After a fortnight of study, I felt that I was now ready to take up my work in the laboratory, but I feared my lack of general knowledge of the city and its ways might still betray me. Hence I began further journeyings about the streets and shops of those levels where a man of my class was permitted to go. ~4~ After exhausting the rather barren sport of walking about the monotonous streets of the four professional levels I took a more exciting trip down into the lower levels of the city where the vast mechanical industries held sway. I did not know how much freedom might be allowed me, but I reasoned that I would be out of my supposed normal environment and hence my ignorance would be more excusable and in less danger of betraying me. Alighting from the elevator, I hurried along past endless rows of heavy columns. I peered into the workrooms, which had no enclosing walls, and discovered with some misgiving that I seemed to have come upon a race of giants. The men at the machines were great hulking fellows with thick, heavy muscles such as one would expect to see in a professional wrestler or weight-lifter. I paused and tried to gauge the size of these men: I decided that they were not giants for I had seen taller men in the outer world. Two officials of some sort, distinguishable by finer garb, walking among them, appeared to be men of average size, and the tops of their heads came about to the workers' chins. That there should be such men among the Germans was not unbelievable, but the strange thing was that there should be so many of them, and that they should be so uniformly large, for there was not a workman in the whole vast factory floor that did not over-top the officials by at least half a head. "Of course," I reasoned, "this is part of German efficiency";--for the men were feeding large plates through stamping mills--"they have selected all the large men for this heavy work." Then as I continued to gaze it occurred to me that this bright metal these Samsons were handling was aluminum!