On account of Mr. Langley’s reliance on the generally sound theory that where a successful method of conducting an experiment has been found only after a long series of failures it is best not to change to some unknown and untried plan, it was impossible, especially where failure in the test might involve a fatal accident, to get him to deviate from his original plan of [p231] launching the large aerodrome from the top of the house-boat. He apparently realized as well as anyone, that in many respects the making of the test from the top of the house-boat had many serious drawbacks, but he emphasized and impressed on the writer the importance of following as far as possible in the construction and test of the large machine, the plans which had brought success with the models. Believing, however, that there was probably a better method of launching the aerodrome than from the top of the house-boat, and that it would be well to prepare before hand as far as possible for following some other plan of launching immediately after a first successful test had been obtained from the top of the boat, Mr. Langley had constructed some floats which were arranged to be attached to the launching car of the quarter-size model so that the car could be converted into a catamaran raft. It was not believed that this crude arrangement would suffice for a complete launching apparatus, since the power of the aerodrome propellers would not be great enough to force the raft through the water at a sufficiently high speed; still it was thought that by having the launching car arranged in this way the model might be allowed to drive the raft rapidly through the water and thus give some idea as to what would be necessary, in a more complete launching apparatus, to obviate the danger of the drag of the raft causing the model to plunge over headlong into the water. The launching car with these floats attached to it, and with the quarter-size model mounted on the car, is clearly shown in Plates 73 and 74.