As a result of these tests it was decided to construct three more wings like this second type, the four forming a complete set for use on the steam-driven models Nos. 5 and 6. Although the tests on the whirling-table indicated a superior efficiency for the “single-tier” wings, and it was not expected that in actual use on the aerodrome the result would be different, yet it was felt that as the conditions of actual use are so very different from those of a whirling-table experiment it would not be safe to decide too definitely against the superposed wings without first giving them a test under actual conditions. Aside from the decreased lifting effect shown by the superposed wing when compared with the “single-tier” one, it was also thought that under the actual conditions of use on the machine the superposed wing would show up still worse. The deflection of the air by the front wings diminishes the lift of the rear ones even for the “single-tier” type, and this, it seemed certain, would be greatly aggravated in the case of the superposed type. In order to emphasize more fully the results of these tests the following table is added, which gives the data for the “single-tier” wing and this second type of superposed one, when each was tested at ten degrees angle of elevation: [Illustration: PL. 64 EXPERIMENTAL TYPE OF SUPERPOSED WINGS, MARCH 2, 1899] [Illustration: PL. 65 EXPERIMENTAL TYPE OF SUPERPOSED WINGS, MARCH 2, 1899] [p193] Wing “Single-tier” Superposed. Type No. 2 Length (feet). 4.27 4.27 Area (sq. ft.). 11.2 21.9 Weight (pounds). 1.26 2.59 Angle of chord. (°) 10 10 Soaringspeed, (ft. per sec.). 11.6 14.3 Weight (lbs. per sq. ft.). .112 .118 Drift (lbs. per sq. ft.). .025 .026 Calculated soaring speed, carrying 0.5 lbs. per sq. ft. (ft. per sec.). 24.5 29.4 The “single-tier” wings actually used on Aerodrome No. 6 were 5.33 feet long, while the wing tested above was only 4.27 feet long. In order to bring out more fully what might be expected of Aerodrome No. 6, when using the two different types of wings, the following table, calculated from the preceding one, is given. This shows the results which might be expected from the aerodrome when the resistance of the machine itself was included: Aerodrome No. 6 without wings weighs 22 pounds.