So 



NATURE 



[May 28, 1896 



open question in the present condition of the inquiry. 

 The close connection with Hallstadt renders the hitter 

 view the more probable, although there is clear ])roof of 

 the Greek influence from the south. This, however, 

 it must be admitted, may belong to a later period. 



In closing this review, we may congratulate Dr. Munro 

 on his success in writing a book which is short, picturesque, 

 and scientific ; and we feel sure that he will gain his end, 

 of attracting attention to the arch;cological treasures 

 awaiting the explorer in this hitherto little-e.xplored corner 

 of Europe. W. BoYU Dawkins. 



EXPERIMENTS IN MECHANICAL FLIGHT. 



T HAVE been for some years engaged in investigations 

 ■'■ connected with aerodromic problems, and particularly 

 with the theoretical conditions of mechanical flight. A 

 portion of these have been published by me under the 

 titles " E.vperimcnts in Aerodynamics " and " The In- 

 ternal Work of the Wind," but I have not hitherto at 

 any time described any actual trials in artificial flight. 



With regard to the latter, I have desired to experiment 

 until I reached a solution of the mechanical difficulties 

 of the problem, which consist, it must be understood, not 

 only in sustaining a heavy body in the air by mechanical 

 means (although this difficulty is alone great), but also in 

 the automatic direction of it in a horizontal and rectilinear 

 course. These difiiculties have so delayed the work, that 

 in view of the demands upon my time, which render it 

 uncertain how far I can personally conduct these ex- 

 periments to the complete conclusion I seek, I have been 

 led to authorise some account of the degree of success 

 which has actually been attained, more particularly at 

 the kind I'equest of my friend Mr. Alexander Graham 

 Bell, who has shown me a letter which he will com- 

 municate to you. In acceding to his wish, and while I 

 do not at present desire to enter into details, let me add 

 that the aerodrome, or " flying-machine " in question, is 

 built chiefly of steel, and that it is not supported by any 

 gas, or by any means but by its steam-engine. This is 

 of between one and two horse-power, and it weighs, 

 including fire-grate, boilers, and every moving part, less 

 than seven pounds. This engine is employed in turning 

 aerial propellers which move the aerodrome forward, so 

 that it is sustained by the reaction of the air under its 

 supporting surfaces. 



I should, in further explanation of what Mr. Bell has 

 said, add that owing to the small scale of construction, 

 no means have been provided for condensing the steam 

 after it has passed through the engine, and that owing to 

 the consequent waste of water, the aerodrome has no 

 means of sustaining itself in the air for more than a very 

 short time — a difficulty which does not present itself in a 

 larger construction where the water can be condensed 

 and used over again. The flights described, therefore, 

 were necessarily brief .S. P. L.^ngley. 



Through the courtesy of Mr. S. P. Langley, Secre- 

 tary of the Smithsonian Institution, I have had on 

 various occasions the privilege of witnessing his experi- 

 ments with aerodromes, and especially the remarkable 

 success attained by him in experiments made on the 

 Potomac River on Wednesday, IVlay 6, which led me to 

 urge him to make public some of these results. 



I had the pleasure of witnessing the successful flight of 

 some of these aerodromes more than a year ago, but 

 Prof Langley's reluctance to make the results public at 

 that time prevented me from asking him, as I have done 

 since, to let me give an account of what I saw. 



On the date named, two ascensions were made by the 



aerodrome, or so-called " flying machine,'' which I will 



not describe here further than to say that it appeared to 



me to be built almost entirely of metal, and driven by a 



NO. 1387, VOL, 54] 



steam-engine which I have understood was carrying fuel 

 and a water supply for a very brief period, and which was 

 of extraordinary lightness. 



The absolute weight of the aerodrome, including that 

 of the engine and all appurtenances, was, as I was told, 

 about 25 pounds, and the distance, from tip to tip, of the 

 supporting surfaces was, as I observed, about 12 or 14 

 feet. 



The method of propulsion was by aerial screw pro- 

 pellers, and there was no gas or other aid for lifting it in 

 the air except its own internal energy. 



On the occasion referred to, the aerodrome, at a given 

 signal, started from a platform about 20 feet above the 

 water, and rose at first directly in the face of the wind, 

 moving at all times with remarkable steadiness, and sub- 

 sequently swinging around in large curves of, perhaps, a 

 hundred yards in diameter, and continually ascending 

 until its steam was exhausted, when, at a lapse of about a 

 minute and a half, and at a height which I judged to be 

 between So and 100 feet in the air, the wheels ceased 

 turning, and the machine, deprived of the aid of its pro- 

 pellers, to my surprise did not fall, but settled down so 

 softly and gently that it touched the water without the 

 least shock, and was in fact immediately ready for another 

 trial. 



In the second trial, which followed directly, it repeated 

 in nearly every respect the actions of the first, except that 

 the direction of its course was different. It ascended 

 again in the face of the wind, afterwards moving steadily 

 and continually in large curves accompanied with a rising 

 motion and a lateral advance. Its motion was, in fact, 

 so steady that I think a glass of water on its surface 

 would have remained unspilled. When the steam gave 

 out again, it repeated for a second time the experience of 

 the first trial when the steam had ceased, and settled 

 gently and easily down. What height it reached at this 

 trial I cannot say, as I was not so favourably placed as in 

 the first ; but I had occasion to notice that this time its 

 course took it over a wooded promontory, and I was 

 relieved of soine apprehension in seeing that it was 

 already so high as to pass 'the tree-tops by twenty or 

 thirty feet. It reached the water one minute and thirty- 

 one seconds from the time it started, at a measured dis- 

 tance of over 900 feet from the point at which it rose. 



This, however, was by no means the length of its flight. 

 I estimated from the diameter of the curve described, 

 from the number of turns of the propellers as given by the 

 automatic counter, after due allowance for slip, and from 

 other measures, that the actual length of flight on each 

 occasion was slightly over 3000 feet. It is at least safe to 

 say that each exceeded half an English mile. 



From the time and distance it will be noticed that the 

 velocity was between twenty and twenty-five miles an 

 hour, in a course which was constantly taking it " up 

 hill." I may add that on a previous occasion I have seen 

 a far higher velocity attained by the same aerodrome 

 when its course was horizontal. 



I have no desire to enter into detail further than I have 

 done, but I cannot but add that it seems to me that no 

 one who was present on this interesting occasion could 

 have failed to recognise that the practicability of 

 mechanical flight had been demonstrated. 



.^I.i;X.\NDER <.'.R.VH.\M BELL. 



THE APPROACHING CELEBRATION OF THE 

 KELVIN JUBILEE IN GLASGOW. 



IT may interest our readers to state the programme of 

 the approaching celebration of the jubilee of Lord 

 Kelvin as Professor of Natural Phflosophy in the Uni- 

 versity of Glasgow. 



On the evening of Monday, June 15, at 8.30 p.m., the 

 University will give a conversazione, when there will be an 



