A.— MATHEMATICAL AND PHYSICAL SCIENCES 29 



contributed papers included Fitzgerald, the late Lord Rayleigh, Oliver 

 Lodge, Lord Kelvin, Barton, Larmor, Carey Foster, Viriamu Jones, and 

 J. J. Thomson. 



During the first fifty years of the Association, it was not uncommon 

 for the Sectional Presidency to be held on more than one occasion by the 

 same man, viz. Whewell and Lord Kelvin were each elected President 

 on five occasions while Brewster, Herschel, the Earl of Rosse, Forbes, 

 Stokes and the then Dean of Ely each held the office twice. Since 1884 

 it has become the practice for the Sectional Chair to be occupied by a 

 newcomer. To this, there has been only one, though a very notable 

 exception, namely Sir J. J. Thomson, who presided in 1896 and again at 

 the memorable Centenary meeting in London in 1931. 



That acoustics was long the Cinderella of the physical sciences is 

 apparent from the sustained Presidential cold-shoulder, though even in 

 the very earliest meetings the subject was not without its supporters. At 

 the second meeting, at Oxford in 1832, Wheatstone read two papers on 

 acoustics, one of them experimental. The Rev. Mr. Wills also gave 

 * An Account of the Recent Additions to our Knowledge of the Phaeno- 

 mena of Sound,' though it is recorded that the printing of the paper was 

 deferred ; which seems to have been a polite way of shelving it 1 



At the 1834 meeting, there was a paper by Addams on ' A New 

 Phaenomenon of Sonorous Interference ' which was accompanied by 

 an experimental demonstration. In the following year at Dublin, there 

 were no fewer than four acoustical papers, including one by Wheatstone 

 ' On the various Attempts which have been made to imitate Human 

 Speech by Mechanical Means,' while in a remarkably penetrating paper 

 ' On the Construction of Public Buildings in reference to the Com- 

 munication of Sound,' Dr. Reid of Edinburgh recognised reverberation 

 as the most prevalent acoustic defect of large rooms and explained how 

 it could be reduced by excluding superfluous space by hanging draperies, 

 or by making the walls more absorbent through greater roughness or 

 irregularity. He also condemned concave surfaces as promoting uneven 

 distribution of sound. Thus the prime and vital factors of good archi- 

 tectural acoustics were clearly recognised as long as a century ago, but 

 did not reach the ear of the architectural profession, so that countless 

 halls with poor acoustics have since been, and still are being erected. 

 The British Association of to-day aims at a more effective publicity in 

 all such matters of general concern. 



Tyndall, during his Sectional Presidency in 1868, gave evidence before 

 a Select Committee on the acoustics of the House of Commons, stressing 

 the value of a low ceiling as a reinforcing device, and the beneficial 

 influence of an audience (as in the Cambridge Senate House) or of 

 draperies in quenching the after-sound in a room. Again, Johnstone 

 Stoney, who was Sectional President in- 1879, described in 1885 a method 

 of treating walls to free concert halls or public rooms from echo effects. 



It was the late Lord Rayleigh, our Sectional President in 1882, to 

 whom with Helmholtz we owe the enduring foundations of a great deal 

 of modern acoustics. Kelvin never said a truer thing when he remarked 

 that progress in a science hinges on measurement ; this indeed is the 



