390 



NA 7 URE 



[August 21, 1890 



blowing at right angles to the direction. On one occasion Jiorses 

 standing close to the base were disturbed by the rumbling sound. 

 When the sand is clapped between the hands a slight hoot-like 

 sound is heard ; but a louder sound is produced by confining it 

 in a bag, dividing the contents into two parts and bringing them 

 together violently. This I had found to be the best way of 

 testing sea-shore sand as to its sonorousness. The sand on the 

 top ot the dune is wind-furrowed, and generally coarser than that 

 of the slope of 31°, but this also yielded a sound of unmistakable 

 character when so tested. A bag full of sand will preserve its 

 power for some time, especially if not too frequently manipulated. 

 A creeping vine with a blue or purple blossom {kolokolo) thrives 

 on these dunes, and interrupts the sounding slope. I found the 

 main slope 120 feet long at its base ; but the places not covered 

 by this vine gave sounds at intervals 160 paces westward. At 

 94 paces further the sand was non-sonorous. 



The native Hawaiians call this place Nohili, a word of no 

 specific meaning, and attribute the sound caused by the sand to 

 the spirits of the dead, uhane, who grumble at being disturbed ; 

 sand-dunes being commonly used for burial-places, especially in 

 early times, as bleached, skeletons and well-preserved skulls at 

 several places abundantly show. 



Sand of similar properties is reported to occur ^iHaula, about 

 three miles east of Koloa, Kauai ; this I did not visit, but, 

 prompted by information communicated by the Hon. Vladimar 

 Knudsen, of Waiawa, I crossed the channel to the little-visited 

 island of Niihau. On the western coast of this islet, at a place 

 called Kaluakahua, sonorous sand occurs on the land side of a 

 dune about 100 feet high, and at several points for 600 to 800 feet 

 along the coast. On the chief slope, 36 feet high, the sand has 

 the same mobility, lies at the same angle, and gives when dis- 

 turbed the same note as the sand of Kauai, but less strong, the 

 slope being so much lower. This locality has been known to the 

 residents of the island for many years, but has never been before 

 announced in print. This range of dunes, driven before the high 

 winds, is advancing southward, and has already covered the road 

 formerly skirting the coast. 



The observations made at these places are of especial interest, 

 because they confirm views already advanced by Dr. Julien and 

 myself with regard to the identity of the phenomena on sea- 

 beaches and on hill-sides in arid regions {Jebel Nagous, 

 Rig-i-Rawan, &c.). The sand of the Hawaiian Islands pos- 

 sesses the acoustic properties of both classes of places ; it gives 

 out the same note as that of Jebel Nagous when rolling down 

 the slope, and it yields a peculiar hoot-like sound when struck 

 together in a bag, like the sands of Eigg, of Manchester (Mass. ), 

 and other sea-beaches — a property that the sand of Jebel Nagous 

 does not possess. These Hawaiian sands also show how com- 

 pletely independent of material is the acoustic quality, for they 

 are wholly carbonate of lime, whereas sonorous sands of all 

 other localities known to us (now over one hundred in number) 

 are siliceous, being either pure silex or a mixture of the same 

 with silicates, as feldspar. 



The theory proposed by Dr. Julien and mystlf to explain 

 the sonorousness has been editorially noticed in Nature, 

 but may properly be briefly stated in this connection. We 

 believe the sonorousness in sands of sea-beaches and of deserts 

 to be connected with thin pellicles or films of air, or of gases 

 thence derived, deposited and condensed upon the surface of 

 the sand grains during gradual evaporation after wetting by the 

 seas, lakes, or rains. By virtue of these films the sand grains 

 become separated by elastic cushions of condensed gases, capable 

 of considerable vibration, and whose thickness we have ap- 

 proximately determined. The extent of the vibrations, and the 

 volume and pitch of the sounds thereby produced after any quick 

 disturbance of the sand, we also find to be largely dependent 

 upon the forms, structures, and surfaces of the sand grains, and 

 especially upon their purity, or freedom from fine silt or dust 

 (Proceedings Am. Assoc. Adv. Sci., 2>^, 1889). 



I should be lacking in courtesy if I closed this letter without 

 expressing my great obligations to Mr. H. P. Faye, of Mai a, 

 and to Mr. Geo. S. Gay, of Niihau, for both a generous 

 hospitality and a sympathetic assistance in carrying out my 

 investigations. H. Carrington Bolton. 



Honolulu, H.I., May 26. 



Relative Growth of Boys and Girls. 



A "note "in NATUREof August 14 (p. 376) referring to some 

 measurements made by Herren Geisler and Ulitzsch on school 



NO. IOS6, VOL. 42] 



children at Freiberg (Saxon), speaks of the fact that between the 

 ages of II and 16 years girls are taller than boys as if it had not 

 been previously observed and recorded. The fact has been well 

 known for many years, and was first observed by Dr. Bowditch, 

 of Harvard. In a private letter to me dated March 13, 1876, 

 Dr. Bowditch wrote : — "A comparison of the rates of growth of 

 boys and girls shows that in this community girls about 13 years 

 of age are talhr and heavier than boys of the same age, and I 

 wish to see how far this is the case in other countries. Quetelet's 

 observations seem to show that it is not the case in Belgium, but 

 some English observations quoted by him indicate that among 

 certain classes of the population in England the same thing is 

 found." Again, on June 10, 1876, he wrote : — " I am exceedingly 

 obliged to you for your letter of April 27, and for the statistics 

 which it contains. I' is very interesting to get a confirmation of 

 my observation on the difference between the two sexes about 

 13 years of age. I shall endeavour to verify your conjecture as 

 to the cause of it. . . . You refer to Quetelet's measurements as 

 being based on only ten observations for each age. Do you 

 understand that the elaborate tables given in his 'Anthro- 

 pometrie,' p. 417, rest entirely on this small number of ob- 

 servations?" In his paper on "The Growth of Children," 

 published the following year (1877), Prof. Bowditch demonstrated 

 the fact by both tables and diagrams ; and in my " Manual of 

 Anthropometry" (1878), and in the Reports of the Anthropo- 

 metric Committee of the British Association (1880-83), I have 

 given similar evidence of the difference of the sexes in this 

 country. The English tables published by Quetelet mentioned 

 by Dr. Bowditch refer to factory children, and were collected by 

 Stanway, and published in a Report of the Factoi-y Commission 

 so long ago as 1833. Quetelet makes his curves of growth of 

 boys and girls meet at the age of 12 years, but at all other ages 

 the girls are shorter than the boys, but his ten observations (on 

 selected individuals ?) at each age were not sufficient to bring out 

 the true difference. The only novelty in the German observa- 

 tions is that the boys do not " catch up " the girls quite so ea:rly 

 as they do in England and "America. This point, however, can 

 only be decided by a comparison of the actual measurements of 

 the German with those of the English and American children. 

 Curzon Street, Mayfair, August 16. Charles Roberts. 



The Perseid Meteors. 



As I merely expressed a wish that the Perseid shower should 

 be closely watched on the present occasion, in order to ascertain 

 whether the apparent shifting of the radiant was not really due 

 to other causes, I do not think I need erter into any controversy 

 with Mr. Denning on the subject. I will therefore only say 

 that I think his " Catalogue of Radiants," recently published by 

 the Royal Astronomical Society (the most valuable catalogue I 

 think which has yet appeared), seems to me susceptible (as re- 

 gards the Perseids) of a different interpretation from that which 

 he places on it in his preliminary remarks, 



Dublin, August 8. W. H. S. Monck. 



In reply to Mr. Monck I need only say that I desired no 

 controversy on this subject, but simply to uphold one of the 

 most conclusive facts of my meteoric observations. I arranged 

 my radiants with the utmost care, and on the basis of a practical 

 acquaintance with the facts ; and if Mr. Monck considers my 

 results in regard to the Perseids will bear another interpretation, 

 I, must be content to wait for the corroboration which future 

 observers will certainly give. 



It is singular that so important a feature as the shifting radiant 

 of the Perseids (which I first announced in Nature, vol. xvi. 

 p. 362) has not yet been adequately investigated. Mr, D. 

 Booth, of Leeds, has, however, effected some observations in 

 recent years (and especially in August 1887), and his results 

 confirm my own. • W. F. Denning. 



Bristol. 



The Eclipse of Thales. 

 Mr. Page, the author of a work entitled "New Light 

 from Old Eclipses," which was noticed in Nature last 

 April, has forwarded the following, communication on the 

 subject of the eclipse of Thales. The views which Mr. Page 

 entertains on the subject of these ancient eclipses are not those 

 generally accepted; but he believes a crucial test of the 

 superiority of his system is aiforded by this particular eclipse > 



