i6 



NATURE 



[August 4, 1892 



where, I send it to you as possibly of interest to some and per- 

 haps of use where practical geometry is being taught. It is 

 evident that the two larger squares are equal, the side of each 

 being equal to the sum of the sides AB, AC of the triangle ABC. 

 It is also clear that the four triangles marked " a " are equal to 



one another. Again, the four triangles marked " (5 " are equal 

 to one another, and to the four triangles marked "a." 



Hence taking four times the triangle "a" from one of the 

 large squares and four times triangle "■ b" from the other, there 

 remain in the one case the square on BC, and in the other case 

 the squares on AB and AC, and these remainders are equal. 

 Therefore the square on the hypothenuse is equal to the sum of 

 the squares on the other two sides. 



A, J. BiCKERTON. 



Canterbury College, New Zealand University, 

 June 15. 



[The principle of the above solution is not new. A proof, by 

 dissection, depending on it is given in several text-books. The 

 novelty of it consists in the position of the squares by means of 

 which the truth of the property is seen in one figure. ] 



Musical Sand. Lava in the Bournemouth Drift. 



In reference to the note in Nature (July 21) respecting musical 

 sand in Australia, permit me to say that the subject has long 

 since received attention there. I am away from references at 

 present, but I should think it must be over two years since 

 Mr. Sidney Olliff kindly sent me samples from Botany Bay. 

 The samples sent were enclosed in small canvas bags, and, 

 though there was probably not more than half-an-ounce of 

 each, they were very musical on reaching me. For purity and 

 musical effect, the Botany Bay samples were more like the Eigg 

 sand than any other kinds I had previously examined. 



During the last five years I have been collecting the various 

 kinds of rock found in the Bournemouth high-level gravels (Cod- 

 rington). A section has lately been exposed at the head of 

 Alum Chine. Here a bed of angular and sub-angular flint 

 gravel 5 ft. (varying) in thickness rests on the Bagshots, and is 

 covered by sand, humus, and peat. At the base of the gravel 

 bed I disinterred (on the 17th inst.) a small piece of vesicular 

 lava, much decomposed in places, but retaining more than suffi- 

 cient of its original structure for purposes of identification. 



The specimen will be sliced for the microscope ; in the 

 meantime I draw attention to it because it is, to my knowledge, 

 the first specimen of vesicular lava that has been found in these 

 gravels. Cecil Carus-Wilson, 



Oxford, July 27. 



The Flora and Fauna of Bromley. 

 The Bromley Naturalists' Society have recently appointed a 

 Special Committee to draw up lists of the flora and fauna of 



NO. II 88, VOL. 46] 



the Bromley Union District. This district comprises the 

 parishes of Beckenham, Bromley, Chelsfield, Chislehurst, Cud- 

 ham, Down, Farnborough, Foots Cray, Hayes, Keston, Knock- 

 holt, Mottingham, North Cray, Orpington, St. Mary Cray, St. 

 Paul's Cray, and West Wickham. 



I am desired to ask you to allow me to state that the Special 

 Committee will be glad to receive from your readers any infor- 

 mation which in their opinion might be of service to the Com- 

 mittee. J. French. 



Hon. Sec. Special Committee. 



99, Widmore-road, Bromley, Kent, July 27. 



THE BRITISH ASSOCIA TION. 



Edinburgh. 



An Edinburgh meeting of the British Association 

 seems almost a home meeting. At every turn we are 

 reminded of some of those who bore their part in found- 

 ing and building up the Parliament of Science. Sir 

 David Brewster meets us in the University quadrangle. 

 The chair now set apart for the President of Section A 

 was occupied for many years by James David Forbes, 

 while for one brief year Natural History in Edinburgh 

 was identified with Edward Forbes, to whom the Asso- 

 ciation owes, among many greater things, the evolution of 

 the Red Lion. Viewed through the vista of years, the in- 

 tellectual life of Edinburgh seems to have been marked 

 by the combination of the love of science and letters 

 with the full enjoyment of social intercourse, and we have 

 before us such evidence of the persistence of this trait as 

 bodes well for the success of the meeting. 



The reception rooms are in keeping with the dignity 

 of the Association, and afford every facility for the trans- 

 action of business. The programme of local arrange- 

 ments which has been put in the hands of members 

 indicates ample variety of occupation for hours of leisure. 

 This pamphlet is of convenient size and easy of refer- 

 ence. In one point of detail it is worthy of remark ; 

 its maps do not require to be unfolded ; these are two, 

 one showing clearly, although on a small scale, Edinburgh 

 and its suburbs, and the other giving, on a large scale, 

 the part of the city which will be most frequently 

 traversed by visitors. The Excursion Handbook has 

 evidently been compiled with much care, and it will 

 prove an interesting and artistic souvenir of the 

 meeting. 



Sir Archibald Geikie, the President of the Association, 

 was President of the Geological section at the 1871 Edin- 

 burgh meeting. His address, suggested by the centenary 

 of Hutton's " Theory of the Earth," deals with a subject 

 in which Scottish geologists have ever been well to the 

 front. The last decade of geological work in Scotland has 

 done much to unlock the secrets of rock structure, and 

 there could be no more fit exponent of the results than 

 ; the president. 



In the section programmes we hear promise of many 

 j welcome papers and several important discussions ; in 

 Section A, on Monday, the question of a National 

 Physical Laboratory will be dealt with ; while Tuesday 

 will be devoted to a discussion on electrical units, in this 

 Prof, von Helmholtz is expected to take part ; Section B 

 and D will consider bacteriology, with special reference 

 to Brewing; Section D, " Fisheries " ; Section F, " Old 

 Age Pensions." In Section C, the feature of the meeting 

 is likely to be the review of recent work in the geology of 

 Scotland, and the presence of a considerable number of 

 foreign geologists is sure to lead to interesting dis- 

 cussions. The Prince of Monaco will give in Section E 

 the results of his observations on ocean currents. Sec- 

 tion G will this year devote some attention to the subject 

 on which there is much difference of opinion, the educa- 

 tion of engineers. 



