4'4 



NA TURE 



[September 3, 1896 



clefinilc shifting of llie centre of gravity to one side would have 

 a more marked effect (since the lateral extension of the whole 

 structure was little more than half of that formerly used), but 

 would also show a greater stability, a result all the more to be 

 expected, as the centre of gravity of the system was placed more 

 than a metre below the upper surface. 



Experiments, which were begun without loss of time, seemed 

 to bear out this conclusion. Lilienthal appeared to have sud- 

 denly gained in power and in the faculty of shaping his motion 

 at will. It seemed to be only a question of time or opportunity 

 that the great step would succeed of describing a complete circle 

 in the air (which always appeared to us to be the key to a definite, 

 if not complete success), when the disastrous accident occurred 

 which has cost the bold experimenter his life. 



The following is, as nearly as I can remember it, the report 

 of the mechanic who used to build Lilienthal's wings, and to help 

 him with his experiments. 



On Sunday, August 9, Lilienthal had gone out to the village 

 Rhinow, where he used to practise on the bare sand-hills in the 

 neighbourhood. Nobody was with him except his mechanic. 

 The weather was exceptionally favourable, a light wind blowing 

 from the east with a velocity of about 5 — 6 m. per second. 



Lilienthal had selected one of these new twostory surfaces, 

 which, in a considerable number of trials from the artificial cone 

 in Lichterfelde, had shown itself to be especially successful. He 

 took one flight, by way of warming to his work, and then pre- 

 pared him.self for a second, and gave the word to his man to 

 look at his watch and note the duration of the flight. The man 

 saw him soar down until he was nearly above the foot of the hill, 

 then suddenly a gust of wind set in, lifted him up to a height of 

 30 m. above the ground — according to his man's estimate — and 

 there he stood apparently motionless in the air. 



This was a frequent occurience, and gave no cause for alarm at 

 first ; but now the man saw how Lilienthal gradually lowered 

 the fore-edge of his wings more and more, without obtaining the 

 desired effect of getting way forward and downward. The man 

 felt uneasy at this, pocketed his watch, and began to run to- 

 wards the spot where his master was hanging suspended in mid- 

 air. Suddenly he saw the apparatus heeling over forward still 

 more, and then Lilienthal came down with it with great force 

 head foremost, rolled over once or twice after striking the ground, 

 and remained motionless. 



When the man reached the spot, he found the apparatus much 

 shattered, but Mr. Lilienthal apparently uninjured thovigh without 

 consciousness. The local physician was instantly summoned, 

 and at first declared that nothing serious had happened. Lilien- 

 thal was brought to the neighbouring inn, and within two hours 

 recovered his senses. He seems to have felt no pain, because 

 he immediately declared he would .soon get up and continue 

 practising. However, his arms and legs were lamed. It appears 

 that his spine was fractured. 



The man left him to the care of the physician, and took the 

 next train to town to fetch his brother. When the brother 

 came, he found that he had swooned again ; and he did not re- 

 cover his consciousness until death set in, which occurred the 

 same night. 



By publishing these lines the editor of Nature will, I 

 think, fulfil a duty he owes the scientific world, as well as 

 the memory of a man who, throughout his toilsome life, applied 

 his rare energy, courage, and ability to the solving of a 

 problem which has hitherto baffled the ingenuity of all modern 

 engineering. 



Lilienthal, who was a successful engineer and manufacturer, 

 has not lived to see his forty-eighth birthday. He leaves a 

 widow and three children. A. DU Bois-REV.MOiNU. 



Berlin, August 24. 



Laboratory Use of Acetylene. 



Now that acetylene has come so much into prominence, an 

 instance of its use in a laboratory which possesses no gas supply 

 may be an encouragement to any one similarly situated. Long 

 doomed to the use of spirit-lamps, " benzoline roarers," and the 

 like, the cheap production of acetylene has come as a great 

 boon to us, and is now in regular use for blow-pipe work. The 

 apparatus in use consists of an aspirator holding about fifteen 

 litres, permanently connected with a water supply, and possessing 

 a i-inch aperture exit tap (the water flows in from below to 

 miQimise absorption) ; at the top a three-hole rubber cork carries 



NO. I 40 I, VOL. 54] 



an upright pipe passing through the table, which serves for 

 filling the aspirator with gas, or using the gas on the table, a 

 second pipe goes to the blow-pipe, and a third carries an open 

 mercury manometer. For filling the jar, the calcium carbide is 

 placed in a four-ounce bottle closed by a cork carrying a small 

 separating funnel from which the water drops ; the gas 

 passes to the aspirator through a wide glass tube which 

 acts a.s a reversed condenser, returning most of the water 

 vapour to the bottle. With the large exit to the aspirator the 

 gas can always be collected under a reduced pressure of several 

 cms. of mercury, which quite provides against any sudden rushes 

 of gas ; the operation takes some ten minutes, and requires 

 practically no attention. 



In using the gas the water is turned on with all taps closed 

 for a few seconds, to correct any reduced pressure caused by 

 absorption, as shown by the gauge (this is very slight 

 indeed), and then the gas-tap fully opened and the flame 

 regulated entirely by the water entrance. To bring llie gas 

 into use takes hardly any longer than with an ordinary gas blow- 

 pipe. A good fusion on platinum foil (e.g. BaS04 -!- Na.^COj) 

 may be eflected by using about one litre of the gas. We have 

 used the apparatus for about two months, and I recently dis- 

 covered that some of my junior workers did not know what 

 acetylene smelt like, which speaks well for it if not for them. 

 I am hoping to introduce the gas on to the benches if the 

 difficulty of the enormous quantity of air required to produce a 

 non-luminous flame can be overcome. A. E. MUNBY. 



The Laboratory, Felsted School. 



Coal-dust. — A Question of Priority. 



In the report of a lecture given in e.flenso at page 64, el sea., 

 in the Colliery Gtiariiiaii, for July 10, on " Coal-dust and 

 Explosives," by Mr. H. Richardson Hewitt, of Derby, H.M. 

 Inspector of Mines, the following remarkable statements 

 occur : — 



" It was but a few years ago that the Messrs. Atkinson first 

 drew attention to their idea that coal-dust was a dangerous 

 element in mines where blasting operations were carried 

 on ... " 



"After Messrs. Atkinson first drew attention to the subject. 

 Prof Galloway took it up and made some rough experiments 

 by placing gunpowder cartridges in heaps of coal-dust and firing 

 them in the dark." 



Although these statements were obviously uttered in ignorance 

 of the nature of my experiments, they raise a distinct and 

 palpable issue as to priority. 



The facts are as follows : — 



My first experiments with coal-dust were made on July 3, 

 1875. I then discovered that a mixture of air and fire-damp, 

 which is not inflammable at ordinary pressure and temperature, 

 on account of the smallness of the proportion of fire-damp 

 present in it, becomes inflammable when coal-dust is added to 

 it, and can be ignited by means of a comparatively small flame. 



On December 22, 1875, I gave evidence in the capacity of 

 Assistant Inspector of Mines at the Coroner's inquest on Llan 

 Colliery Explosion (South Wales District), when I attributed 

 that explosion principally to the influence of coal-dust. My 

 evidence was discountenanced by the Chief Inspector of Mines 

 for the district, and was not embodied in the Reports of the 

 Inspectors of Mines, but it was reported verbatim in the two 

 local newspapers ( Western Mail and South IVales Daily News) 

 of December 23, 1875. 



On March 2, 1876, I read my first paper, entitled "On the 

 Influence of Coal-dust in Colliery Explosion.s," before the Royal 

 Society. In that paper I announced the coal-dust theory. 



In 1878 I published a large number of articles in Iron, under 

 the title of " Coal-dust Explosions." In these articles, amongst 

 many other things, I quoted and commented upon what Earaday 

 and Lyell had written about coal-dust upwards of twenty years 

 previously, and I gave complete translations of the papers that 

 had been published in France, having a bearing upon the 

 subject. 



Besides contributing a number of other articles and papers 

 on the same subject to various societies and periodicals, I read 

 altogether five papers " On the Influence of Coal-dust in Colliery 

 Explosions" before the Royal Society, viz. : March 2, 1S76, 

 already referred to; February 27, 1879: May 30, 1S81 ; 



