4IO 



NATURE 



[Sept. 17, 1874 



" Prof. Dana further believes that many of the lagoon islands 

 in the Paiunotu or Low Archipelago and elsewhere have recently 

 lieen elevated to a height uf a lew feet [elsewhere stated, two or 

 three feet] although formed during a period of subsidence ; but I 

 shall endeavour to show, in the sixth chapter of the present 

 edition, that lagoon islands which have long remained at a sta- 

 tionary level often present the false appearance of having been 

 slightly elevated." And, in the body of the work, where the 

 subject is taken up (p. 16S), Mr. Darwin remarks that my belief 

 in these small local elevations is grounded chiefly on the shells 

 of Tridacnas embedded, in their living positions, in the coral 

 rock at heiglits where they could not now survive. 



The catalogue of such elevations which I give (p. 345) — after 

 a dozen pages devoted to a discussion of the evidence respecting 

 each — is as follows : — 



Paumotu Archipelago Honden 2 or 3 



,, ,, Clermont Tonnerre ... 2 or 3 



,, ,, Nairsa or Dean's ... 6 



,, ,, Elizabeth So 



,, ,, Metia or Aurora ... 250 



,, ,, Ducie's lor 2? 



Tahitian Group Tahiti o? 



,, ,, Bolabola ? 



Hervey and I'lurutu Groups.. Atiu 12? 



,, ,, ,, Mauke ... somewhat elevated. 



„ ,, ,, Mitiaro ... ,, ,, 



,, ,, ,, Mangaia 300 



,, ,, ,, Rurutu 150 



,, ,, ,, Remaining Islands ... o? 



Tongan Group Eua 300? 



,, ,, Tongatabu 50 to 60 



,, ,, Namuka and the llapaii 25 



„ ,, Vavau 100 



Savage Lsland 100 



Samoan or Navigator Islands o 



North of .Samoa Swain's 2 or 3 



,, ,, Fakaafo, or Eowdilch 3 



,, ,, Oatafu, or Duke of York's 2 or 3 



Scattered Equatori.il Islands Washington 2 or 3? 



,, ,, ,, Christmas ? 



,, ,, ,, Jarvis's 8 or 10 



,, ,, ,, Maiden's 250130 



,, ,, ,, Starbuck's.. ? 



,, ,, ,, Penrhyn's 35 



,, ,, ,, Flint's and Staver's... ? 



,, ,, ,, Baker's ^ or 6 



,, ,, ,, riowland's ? 



,, ,, ,, PhiLuix and McKeau's o 



,, ,, ,, Enderbury's 2 or 3? 



,, ,, ,, Newmarket 6orS? 



,, ,, ,, Gardner's, Hull's, Sydney, 



IJirnie's o ? 



Feejee Islands Viti Levu and Vanua 



Levu, Ovalau ... 5 or 6? 

 Eastern Islands ... o? 



North of Feejees Home, Wallis, Ellice, 



Depeyster o? 



Sandwich Islands Kauai i or 2 



,, ,, Oahu 25 or 30 



,, ,, Molokai 300 



,, ,, Maui 12 



Gilbert Islands T.apufcuea 2 or 3 



,, ,, Nonouti, Kuria, Maiana, 



and Tarawa 3 or more. 



,, ,, Apamama 5 



,, ,, Apai.ing or Charlotte. 6 or 7 



,, ,, Marakei 3 or more. 



Makin ? 



Carolines McAskill's 60 



Ladrones Guam 6co 



,, Rota 600 



Feis 90 



Pelews o? 



New Hebrides, New Caledonia, 



Salomon Islands none ascertained. 



Of the cases of elevation here included, in only two are shells 

 of Tridacnas mentioned; these are llonden Island and Cler- 

 mont Tonnerre, in the I'aumotus. It is not necessary to go over 

 the evidence for the several cases, as it is slated at length iu my 

 work. 



Mr. Darwin, while speaking on the subject of local elevations, 

 on p. 176, and discussing the iacts as regards the Samoan (Navi- 

 g.itor) Isl.ands, adds that "in another place he [Mr. DanaJ says 

 (p. 326) that some of the [.Samoan] islands have probably suIj- 

 sided." From the remark the reader would infer that tliis 

 Samo.in subsidence was a local subsidence, like the elevations 

 under consideration. But in fact my statement is in a chapter 

 on the gener.^1 coral-island subsidence, and, on the page there 

 referred lo (p. 326), I cite Mr. Darwin's conclusions as to the 

 Gambler Island subsidence, and put with it my own from the 

 width of the reefs of Upolu and otlier reef bordered islands. At 

 the same jdace I allude to the greater subsidence of Tutuila — tlie 

 island next to the west, as proved by its bold shores and small 

 reefs. 



In conclusion, if I differ widely, for the reasons above stated, 

 from Mr. D.\rwin, as to the limits of the areas of subsidence and 

 elevation in the Pacific, and believe that the new edition of his 

 work .shows litlle appreciation of some of the most important 

 causes that have limited the distribution of coral reefs, I have, as 

 I say in my work, the fullest satisfaction in his theory for the 

 origin of atoll and barrier forms of reefs, and in the array of facts 

 of his own observation which illustrate the growth of coral for- 

 mations. James D. Dana 



THE BRITISH ASSOCIATION 

 Reports 



Rtfott of the Committee on the Teaching of Physics in Schools, 

 by Prof. G. C. Foster. 



In view of the very great diversities in almost all respects of 

 the conditions under which the work of different schools has tc 

 be carried on, the committee considered that in any suggestions 

 or recommendations that they might make it would be impos- 

 sible for them, with any advantage, to attempt to enter into details. 

 They have therefore, in the recommendations which they have 

 agreed upon, endeavoured to keep inviewceitain principles which 

 they regard as of fundamental importance, without attempting 

 to ]irescribe any particular way of carrying them out in practice. 



They have assumed as a point not requiring further discussion, 

 that the object to be r^ttained by introducing the teaching of 

 physics into general school-work is the mental training and disci- 

 pline which pupils acquire through studying the methods whereby 

 tlie conclusions of physical science have been established. They 

 are however of opmion that the first and one of the most serious 

 obstacles in the way of the successful teaching of the subject is 

 the absence from the pupil's mind of a firm and clear grasp of 

 the concrete facts and phenomena forming the basis of the reason- 

 ing procfsses they are called upon to study. 



They therefore think it of the utmost importance that the first 

 teaching of all branches of physics should be, as far as possible, 

 of an experimental kind. Whenever circumstances admit of it, 

 the experiments should be made by the pupils themselves and not 

 merely by the teacher, and though it may not be needful for every 

 pupil to go through every experiment, the committee think it 

 essential that every pupil should at least make some experiments 

 himself. For the same reasons they consider that the study of 

 text-books should be entirely subordinate to attendance at expe- 

 rimental demonstrations or lectures, in order that the pupil's first 

 impressions may be got directly from the things themselves, and 

 not from what is said about them. They do not suppose that it 

 is possible in elementary teaching entirely to do without the use 

 of text-books, but they think they ought to be used for reviewing 

 the matter of previous exiedmental lessons rather than in pre- 

 paring for such lessons that are to follow. 



With regard to the order in which the different branches of 

 physics can be discussed with greatest advantage, considering that 

 all explanation of physical phenomena consists in the reference 

 of them to mechanical causes, and that therefore all reasoning 

 about such phenomena leads directly to the discussion of me- 

 chanical principles, the committee are of opinion that it is 

 desirable that the school teaching of physics should begin Willi a 

 course of elementary mechanics, including hydrostatics and 

 pneumatics, treated from a purely experimental ]ioint of view. 

 Tlie committee do not overlook the f.ict that very little jirogress 

 can be made in theoretical mechanics without considerable fami- 

 liarity with the processes of mathematics, but they believe that 

 by making constant appeal to experimental proofs the study of 

 mechanics may be profitably begun by boys wlio have acquired 3. 

 fair knowledge of arithnielic, including decimals and proportion, 



