February 4, 1909] 



NATURE 



41, 



which was given an excellent account of the Clyde islands. 

 Contemporary with MaccuUoch was another observer to 

 whom Scottish geology stands deeply indebted, Ami Bou(J. 

 After taking his degree in Scotland Bou6 went to Paris, 

 where for a time he employed himself in preparing his 

 " Essai g^ologique sur I'Ecosse," which saw the light in 

 the year 1820. A few native inquirers began to make their 

 appearance during the closing years of the eighteenth and 

 the early decades of the nineteenth century as pioneers in 

 the investigation of the details of the local geology. First 

 came David Ure, whose excellent " History of Rutherglen 

 and East Kilbride," published in 1783, stands out pre- 

 eminent for the fulness and faithfulness of its descriptions. 

 Afterwards came Andrew C. Ramsay. After referring to 

 the work of John Craig in Lanarkshire, Montgomery in 

 Renfrewshire, Prof. Thomas Thomson in Glasgow Uni- 

 versity, and James Bryce, Sir .Archibald Geikie said that 

 of all the influences which conspired to raise in Glasgow 

 an interest in the geological history of the district he was 

 dispo.sed to give the foremost place to that of James 

 Smith, of Jordanhill. 



THE WIXXIPEG MEETIXG OF THE BRITISH 

 ASSOCIATION. 



A CIRCUL.XR has been prepared containing information 

 -^*- of interest to members of the British Association who 

 propose to attend the meeting to be held in Winnipeg, 

 •Manitoba, Canada, in August next, under the presidency of 

 Sir J. J. Thomson, F.R.S. A representative local executive 

 committee and officers have been appointed to conduct the 

 local arrangements, which will include some interesting 

 excursions and facilities for a tour through the Western 

 Provinces to the Pacific Coast. The weather conditions 

 during the latter part of .August and the beginning of 

 September are favourable In the Western Provinces of 

 Canada, whilst in Winnipeg, situated 760 feet above sea- 

 level, the days are warm, though not oppressively hot, 

 and the nights are invariably cool. On account of .August 

 being the busiest month of the year in bookings to 

 .America, no reduction on minimum steamship rates will 

 be made to members of the association, but superior 

 accommodation may be granted, on the return voyage, at 

 the ordinary minimum rate. The journey to Winnipeg, 

 the meeting, and return home will take about thirty-two 

 days. There will be a western excursion from Winnipeg 

 to Regina, Moose Jaw, Calgary, Edmonton, Vancouver, 

 and Victoria, and return to Winnipeg ; members who 

 take part in this excursion will require ten more days, 

 thus making a si.x weeks' visit. Special fares are expected 

 to be in force on the Canadian railways, amounting prob- 

 ably to a single fare for the return journey, from Nlontreal 

 to Winnipeg, provided the party numbers not less than 

 fifty ; as also from Winnipeg to Vancouver, or for any 

 side-trip made by Individual members. The estimated per- 

 sonal expenditure of each member attending the meeting 

 from Great Britain is a minimum of about 38/.. and 

 an average of about 65?. The additional expense of the 

 western excursion will be about 25?. .Any member of the 

 association who contemplates an extensive journey of 

 exploration or for other scientific purposes, fishing, hunt- 

 ing, &c.. is invited to communicate with the local secre- 

 taries of the British .Association, University of Manitoba, 

 Winnipeg. Expert advice and assistance will be given to 

 any group of members who propose to avail themselves of 

 this opportunitv. .A list of hotels and lodgings will be 

 issued by the Winnipeg executive officers, to whom applica- 

 tion should be made, early in Julv. 



Afembers who propose to attend the meeting should send 

 in their names to Mr. H. C. Stewardson. assistant treasurer 

 of the British .Association, Burlington House. London, W.. 

 not later than May -^i. by which date members should, if 

 possible, complete their arrangements with the steamship 

 companies, as all the best accommodation on steamers 

 sailing in .August is booked some months ahead. .An illus- 

 trated handbook of preliminary information, issued by the 

 Winnipeg executive committee, will be forwarded from the 

 olllce of the association on receipt of 2i(J. for postage. 

 N'O. 204Q, VOL. 79] 



MECHANICAL FLIGHT.' 

 Present Position. 

 'X'HE recent records made by Messrs. Wright, Farman, 

 -*■ Delagrange, and Bleriot, together with the gradual 

 accumulation of testimony in favour of mechanical flight, 

 have finally disabused both the public and experts of the 

 notion that aviation is a dream. 



Many engineers from time Immemorial have tackled the 

 subject without success, and there was every reason for 

 the sceptical attitude which has prevailed until the last 

 few years. It Is now evident that mechanical flight was 

 impossible before science and engineering skill in the nine- 

 teenth century had so perfected the heat engine that con- 

 siderable power was obtainable with but little weight. 

 The present improved aspect of affairs must not, however, 

 blind us to the fact that much has yet to be done. The 

 most successful machines now In existence show serious 

 defects, cannot be manipulated in troublesome weather, 

 and have every part so light that at all times they are 

 on the brink of collapse. It rests with mechanical 

 engineers to design a stronger machine without losing 

 efficiency. In the course of this paper the author proposes 

 to indicate certain points in which Improvement is desired, 

 and at the same time he has endeavoured to include a 

 sufficiency of the theoretical and experimental knowledge 

 available on the subject to enable a would-be aviator to 

 construct a simple type of machine. 



It cannot be too strongly realised that existing Informa- 

 tion Is defective, and a few words as to research may be 

 useful. 



Ncccssitv for Research. 

 It will be shown in the course of this paper that the 

 whole question of mechanical flight depends upon a know- 

 ledge of the manner in which air reacts against solid bodies 

 moving through it. -A large number of researches have 

 been made during the past 150 years, but even yet exact 

 Information is lacking on the majority of points. 



Furthermore, mathematical analysis has not been suffici- 

 ently developeti. A few great mathematicians (including 

 Lords Kelvin and Rayleigh) have devoted some attention 

 to the matter, but the author Is not aware that any mathe- 

 matician worthy of the name has considered it worth while 

 to make an exhaustive study of the question, although It 

 must be recognised that the recent advances In the theory 

 of hydrodynamics form useful auxiliaries to the study of 

 aerodynamics. 



Brief History of the Theory. 

 The nature of fluid resistance has been investigated for 

 many years, and the general principles are to be found 

 in Newton's " Principia." The ballistic researches of 

 Hutton and Robins at the end of the eighteenth century 

 first clearly showed the quantitative value of air resist- 

 ance, and their work is still valuable. On the hypothesis 

 deducible from Newton's work, Messrs. Navier and Gay- 

 Lussac early in the nineteenth century formulated a theory 

 of flight which showed that great power was necessary, 

 and this notion held sway for many years after, so that 

 little progress was made with the subject, flight being 

 deemed impracticable. Experiments by Wenham and 

 Browning in the 'eighties, together with Langley's re- 

 searches in .America and Maxim's in England, clearly 

 showed the fallacy of this idea. P^naud in 1876 first gave 

 the mathematical theory of the aeroplane, which had been 

 conceived by Henson in 1840. The late Mr. Froude, Lord 

 Rayleigh, and Prof. Bryan developed this theory, and in 

 iqo3 the last-named produced equations of stability for 

 the aeroplane. Two years later Captain Ferber, of the 

 French artillery, amplified these equations to find the con- 

 ditions of lateral stability and the form of the trajectory, 

 and quite recently Mr. Lanchester has done similar work. 

 Prof. Fitzgerald and Lord Rayleigh have gis'en some atten- 

 tion to the ornithopt&re, and Profs. Pettigrew and Marey 

 at an earlier date arrived at several important conclusions 

 respecting bird flight. The helicoptJre has not received 

 very much attention, but the cognate work of the late Mr. 

 Froude and his son on propellers has a most important 

 t .Abridged from a Daper y Mr. Herbert Chatley read before the Society 

 t Engineers on DeceTiber 7, 1908. 



