October i, 1896] 



NA TURE 



523 



variation is correlated with a certain death-rate, it must be the 

 cause of it, and that it is not possible to distinguish between 

 variations which are directly useful, and those which are only 

 physiolo^jically correlated with the useful. But it seems to me 

 that this is like talking of hitting a nominative case with a stick. 

 The variation is a magnitude in an organism, survival or death 

 is a relation between the organism and its environment. It is 

 the relation of the variation to life which altme can be said to be 

 the cause of death or survival. The relation to the conditions 

 of life is advantage, disadvantage, or neutrality in the struggle 

 for existence. If I have slated the logic of the matter correctly, 

 I venture to think that the apprehension of this principle is a 

 necessary preliminary to any attempt to demonstrate empirically 

 the occurrence of natural selection. 



Prof. Weldon's chief contention was that by the statistical 

 method, when the law of growth of the characters examined 

 was known, a measure of the rate and direction of the evolution 

 of an organism could be obtained. Such a measure would be 

 aflforded by the selective death-rate. But he has not yet 

 demonstrated a selective death-rate in a single instance. And 

 further, a measure of the rate and direction of evolution has 

 nothing to do with the cause of the selective death-rate. If 

 characters of no apparent utility are proved to be subject to 

 selection, there still remains the question how the selection is 

 brought about. Measures of the rate and direction of the wind 

 do not tell us the cause of the wind. They may help us to 

 discover the cause, and I have nu doubt that Prof. Weldon's 

 investigations are a valuable contribution to the investigation 

 of evolution. But it is only when it has been shown that the 

 degree of utility of a variation, or its correlation with useful 

 variations determines its survival, that the occurrence of natural 

 selection has been demonstrated. J. T. Cunningham. 



September 19. 



Fossil Tridacnids in the Solomon Islands. 



Some months ago, on the voyage between New Guinea and 

 Sydney, the small trading steamer on which I travelled called at 

 a number of islands in the British Solomons, the first station at 

 which we called being Rubiana, in the little-known island- 

 complex of New Georgia. Here I became acquainted with the 

 heavy arm-rings worn by the natives, and obviously made from 

 the shell of Tridacna or Hippopiis. What was very surprising, 

 however, was the information which I obtained from all quarters 

 and from different localities, from blacks as well as from whites, 

 that these arm-rings are not made from recent shells found on the 

 reef, but from shells obtained far away in the interior, or, as 

 they say, in the bush. At first sight, the arm-rings, above 

 referred to, strongly remind one of those made from the recent 

 Triilaciia by the natives of the Sir Charles Hardy Island, which 

 lies to the north of the Solomon Group ; but while the former 

 are .solid rings more than half an inch in thickness, the latter 

 are deeply grooved on the outer border. 



This difference is shown in Figs. I and 2, which represent 

 cross-sections through the arm-rings of the Solomon and Sir 



Charles Hardy islanders, respectively. But there are other 

 differences, not so much of artistic as of economic importance. 

 The grooved rings are much more readily obtained from the 

 natives whcj make and wear them, than are the solid rings. The 

 latter have a great value among the natives themselves, and 

 when they are shot with a vein of reddish or reddish-yellow 

 colour (derived no doubt from the hinge-line, which also gives 

 their beauty to the nose-pieces of the New Guinea natives), they 

 can only be mentioned with bated breath. 



The reason why the Solomon Islanders prefer the ancient to 

 the recent shells, lies possibly in the fact that, as a general rule, 

 among ihe natives of the larger islands of the Pacific, the 

 artists and artificers (apart from the making of canoes) are to be 



NO. 1405, VOL. 54] 



found among the bush-natives, rather than among those who live 

 in proximity to the sea. The latter are traders;/^?- excellence — 

 men of the world who do their business in great waters. The 

 former live in primitive innocence, are possessed of uncouth 

 manners, and produce poets, magicians, medical men, and pro- 

 fessional dancers, together with workers in wood and stone. To 

 the last-mentioned members of the community, therefore, the 

 Tridacnid shells, when they occur in the bush through elevation 

 of a former coral reef, are ready conveniently to hand. 



I have thought it worth while to draw the attention of 

 naturalists to the above indication of the existence of upraised 

 coral reefs in the Solomon Islands, which would be well worth 

 an attentive examination, and, while in Sydney, Mr. R. 

 Etheridge, jun., informed me that he knew of other instances in 

 the Pacific of coral reefs having been raised to an elevation of 

 over a thousand feet. Arthur Willey. 



Noumea, New Caledonia, July 16. 



Visual Aid in the Oral Teaching of Deaf Mutes. 



Probably every one is acquainted with Kojnig's manometric 

 capsules and revolving mirrors, and it occurred to me that I 

 might help a deaf mute to learn inflection in speaking by his 

 imitating the curves produced by my voice in the mirrors. For 

 this purpose I arranged two capsules with oblique membranes 

 and small diameter side by side, one being higher than the 

 other, so that two bands of flame half inch wide, and half inch 

 apart, appeared in the revolving mirrors. The capsules were 

 tuned alike, and furnished with tubes and conical mouthpieces ; 

 through one of these I made the sound of a note, vowel, or 

 syllable in various pitches, and my friend endeavoured to imitate 

 through the other tube the curve in the flame band produced by 

 my voice. As an experiment the results were quite satisfactory, 

 for before an hour was over he could imitate a range of nearly 

 an octave, and would tell me correctly, through watching the 

 curves of flame, when the note he uttered was like mine. I am 

 not interested in the oral teaching of the deaf, but having fre- 

 quently to use Koenig's invention, I think the principle might be 

 made useful to oral teachers. My friend, upon whom I experi- 

 mented, is said to have been well taught, his age about twenty 

 years, but his voice (?) is a hoarse monotone. T. Hawksley. 



II Primrose Hill Road, N.W. 



INTERNATIONAL METEOROLOGICAL 

 CONFERENCE AT PARIS. 



THIS Conference was held at the rooms of the Societe 

 d'Encouragement, in the Rue de Rennes, from 

 September 17 to 23. About forty members were present. 

 M. Mascart was elected President, MM. de Bezold and 

 Tacchini Vice-Presidents, and MM. Angot, Erk, and Scott 

 Secretaries. The complete report of proceedings has not 

 yet been printed. It was decided that Committees should 

 be appointed to continue the investigation of several 

 subjects, viz. : 



I. Terrestrial Magnetism and Atmospheric Electricity ; 

 Prof. Riicker (President). 



II. Clouds ; Prof. Hildebrandsson (President). 



III. Radiation and Insolation ; M. Violle (President). 



IV. Aerostatics and Balloon Work; Prof. Hergesell 

 (President). 



On the motion of Mr. Symons, the International 

 Meteorological Committee was reappointed with a few 

 changes, rendered necessary by the respective resigna- 

 tions of Prof. Wild, Prof Harrington, and Mr. Ellery. 

 The President is Prof Mascart, and the Secretary Mr. 

 R. H. Scott. 



ARMAND HIPPOLYTE LOUIS FIZEAU. 



BY the death of M. Fizeau physical science has lost 

 one who will rank high among those vyho have 

 contributed to the scientific distinction of the nineteenth 

 century. Every student of optics knows M. Fizeau's 

 beautiful experimental inethod of determining the velocity 

 of light ; but not so many are aware of the other re- 



