230 



NA TURE 



[yuiy 23, 1874 



THE FLYING MAN 



TH E fatal experiment made by M. de Groof at Cremovne 

 Gardens could not possibly have led to success. The 

 possibility of directin<; an apparatus in the air by any 

 mechanical contrivance, without actually using the lifting 

 power of gas, is out of the question, and we do not wish to 

 enter into a discussion on that point. But several interest- 

 ing problems may be examined a propos of the inquest 

 held by the coroner on the death of the unfortunate man. 



De Groof's wings, irrespective of their motive power, 

 may be regarded as two imperfect parachutes intended 

 to diminish his rate of falling, and, if kept horizontal, 

 prevent it increasing above a certain rate. It remains 

 to see if their surface was large enough to keep that 

 velocity within reasonable limits. The wings of De 

 Groof were 30 ft. by \ ft. ; but being irregularly shaped, we 

 may suppose the surface of each was 100 sq. ft., or in 

 round numbers 200 sq. ft. for the two. The weight of the 

 machine not being far from 4cwt. if we include the man, 

 we may say in gross numbers that each square foot had a 

 kilogramme to support, which is more than ordinary ; 

 the parachute maker taking i kilogramme for each 

 square metre, which is about ten times smaller. 



But to ascertain if the velocity, although being larger 

 than under ordinary circumstances, was really dangerous 

 we must go to the formuk-c established by General Didion 

 and quoted by Poucelet — ■ 



R = I '936 {A O'o36 + o'oS4 v-) 

 Under the above circumstances, R the rate of falling is 

 always inferior to the value of x given by the equation 



10 = r936 (o'036 + o'oS4.i--) 

 X being obviously enough the velocity for which i? = to 

 the weight pressing on the unit of surface. When the 

 motion is such the velocity cannot be increased. If we 

 make the calculation it is easy to see that the velocity is 

 about 7 metres per second, almost = the fall from 3 metres 

 to the ground. It is large, but not too large for a prac- 

 tised jumper, if he v/ere clever enough to keep hisbalancCj 

 which is not very easy, it must be confessed. 



Experiments on parachutes show that great oscillations 

 always take place if the exjierimenters have not placed a 

 small hole in the centre of their parachute, which increases 

 stability at the expense of resistance. The motion of the 

 wings, if they are working together, would very likely 

 render the same service to the occupant of the machine, 

 as they prevent the accumulation of the air. Unfortu- 

 nately, to keep them v/orking evenly is a difficult matter, 

 requiring not only force of muscle but great presence and 

 firmness of mind. The so-called queue or rudder was a 

 useless encumbrance. A man working hard with his two 

 hands, fighting for his life, cannot be expected to attend 

 to direction with his legs attached to a rudder. The 

 lifting power of the wings must have been very small 

 indeed, although diminishing in some respects the rate of 

 falling ; but it is not easy to understand how a calculation 

 may be made of the amount of mechanical power exerted 

 in each stroke. The question must be left open for future 

 examination. W. DE FONVIELLE 



NOTES 



A CIRCULAR has been issued by the Hon. Local Secretaries of 

 the Belfast meeting of the British Association, calling attention 

 to the numerous objects of interest, natural and mechanical, with 

 wliich the town and neighbourhood of Belfast, as well as the 

 county of Antrim, abounds. The whole Province of Ulster is 

 full of objects of the highest interest to the admirer of natural 

 scenery, to the geologist, the naturalist, and the antiquarian ; 

 and many of its most interesting localities, such as the Antrim 

 Coast, the Giant's Causeway, the Mourne Mountains, Lough 

 Neagh, the Round Towers of Antrim and D rumbo, are within 



an easy distance of Belfast. The local secretaries state that a 

 large number of the hotels will be open to members of the Asso- 

 ciation at the usual charges, and that a list of persons willing to 

 let rooms has been prepared. AVe sincerely Iiope that this time 

 there will be no complaint to make on the score of accommo- 

 dation. Conveyance to Belfast can be obtained from any part of 

 the country at very reasonable rates. 



The Right Hon. Lord O'Haganwill preside over the Section 

 for Economic Science at the meeting of the British Association. 



A MEETING of the General Council of the Yorkshire College 

 of Science was held at Leeds on the I7tli inst. The Council 

 proceeded to the election of the Professor of Geology and 

 Mining, and the Professor of Physics and Mathematics. The 

 vote ol the Council was unanimously given to Mr. A. H. Green, 

 M.A., late Senior Fellow of Gonville and Caius College, Cam- 

 bridge, as Professor of Geology ; and Mr. A. W. RUcker, 

 M.A., Fellow of Brasenose College, Oxford, as Professor 

 of Physics and Mathematics. Prof. Green for the last 

 five years has held the appointment of Lecturer on Geology 

 at the School of Military Engineering at Chatham. Prof. 

 RUcker in Oct. 1S71 was appointed Demonstrator in the 

 Physical Laboratory of Oxford University under Prof. Clifton. 

 The appointment of the Professor of Chemistry will be made 

 on Friday. The Council recorded a cordial vote of thanks to 

 Sir A. Fairbairn for his liberal offer of 2,000/. , provided that the 

 sum of 60,000/. was placed in the hands of the treasurer, and 

 resolved to take the necessary steps for raising the required 

 amount. 



At King's College, London, the Chair of Zoology and Com- 

 parative Anatomy, vacated by the resignation of Prof T. Rymer 

 Jones, F.R.S., has been filled by the election of Mr. A. H. 

 Garrod, Fellow of St. John's College, Cambridge, and Prosector 

 to the Zoological Society. The Chair of Materia Medica and 

 Therapeutics, vacated by the resignation of Prof. A. B. Garrod, 

 M.D., F.R.S., has been filled by the election of Dr. E. B. 

 Baxter, Medical Tutor to the College. 



The prospectus has just been issued of a company to establish 

 an aquarium for London, close to Westminster Abbey. 



A ItALLOON experiment to test a steering apparatus is soon to 

 be made under the auspices of the authorities at Woolwich. 



NoRTllUMr.ERLAM), in Pennyslvania, on the Susquehannah, 

 the place where Dr. Priestley was buried, has been selected by 

 Americans as the spot at which all chemists are invited to gather 

 on August I next, the hundredth anniversary of the discovery of 

 o.xygen by the illustrious philosopher. An address is to be delivered 

 over his grave. This proposition of Dr. Bolton has met with a 

 cordial response from a large number of chemists. Prof. Plenry, 

 of the .Smithsonian Institution, proposes to be present with 

 some of the original apparatus of Priestley from the Smithsonian 

 collections. August i falling on Saturday, the meeting will be 

 called for the day previous. A programme will be scon issued 

 by the committee in charge. 



The Governing Body of Christ Church, Oxford, have voted 

 the sura of 100/. per annum for five years in aid of the Biological 

 Department of the Museum. 



The New Falcons' Aviary in the northern part of the Zoolo- 

 gical Society's Gardens be)ond the canal has just been com- 

 pleted, .ind is now tenanted by a fine scries of the Diurnal Birds of 

 Prey, principally exotic. Amongst them are examples of several 

 rare species, such as the Red-backed Buzzard {Biilco eiylhro- 

 no/us), the Laughing Eagle (f/erpclol/iins cachiiinanis), and the 

 Malayan Crested Kagle {Sphaclus caligatus). Amongst the less- 

 known liuropean species are a pair of Bonelli's Eagles, a pair of 

 Red-footed Falcons, and an Elconora Falcon. 



