If it had been the initial intention of the designers to operate their cars to the second platform, they must shortly have become aware of the impracticability of this plan, caused by an inherent characteristic of the apparatus. As long as the compressive force acted along the longitudinal axis of the links, there was no lateral resultant and the only load on the small rollers was that due to the dead weight of the link itself. However, if a curve had been introduced in the guide channels to increase the incline of the upper run, as done by Otis, the force on those links traversing the bend would have been eccentric--assuming the car to be in the upper section, above the bend. The difference between the two sections (based upon the Otis system) was 78°9' minus 54°35', or 23°34', the tangent of which equals 0.436. Forty-three percent of the unbalanced weight of the car and load would then have borne upon the, say, 12 sets of rollers on the curve. The immense frictional load thus added to the entire system would certainly have made it dismally inefficient, if not actually unworkable. In spite of Eiffel's public remarks regarding the safety of the Roux machinery, in private he did not trouble to conceal his doubts. Otis' representative, Hall, discussing this toward the end of Brown's previously mentioned report, probably presented a fairly accurate picture of the situation. His comments were based on conversations with Eiffel and Koechlin: Mr. Gibson, Mr. Hanning [who were other Otis employees] and myself came to the unanimous conclusion that Mr. Eiffel had been forced to order those other machines, from outside parties, against his own judgment: and that he was very much in doubt as to their being a practical success--and was, therefore, all the more anxious to put in our machines (which he did have faith in) ... and if the others ate up coal in proportions greatly in excess of ours, he would have it to say ... "Gentlemen, these are my choice of elevators, those are yours &c." There was a published interview ... in which Eiffel stated ... that he was to meet some American gentlemen the following day, who were to provide him with elevators--grand elevators, I think he said.... [Illustration: Figure 30.--Upperworks and passenger platforms of the Otis system at second level. (From _La Nature_, Aug. 10, 1889, vol. 17, p. 169.)] The Roux and the Otis systems both drew their water supply from the same tanks; also, each system used similar distributing valves (fig. 32) operated from the cars. Although no reports have been found of actual controlled tests comparing the efficiencies of the Otis and Roux systems, a general quantitative comparison may be made from the balance figures given for each (p. 40), where it is seen that 2,665 pounds of excess tractive effort were allowed to overcome the friction of the Otis machinery against 13,856 pounds for the Roux. THE EDOUX SYSTEM