yuly 23, 1874] 



NATURE 



235 



is found necessary to produce and to maintain them. In heat- 

 harmonicons the action is less simple, the alternations of 

 pressure as well as the oscillations of the air determining the ad- 

 mission of the entering puffs. To judge from the position in 

 which a singing-ilame sounds best in a chemical harmonicon, a 

 certain " lead " like that used in admitting steam to the cylinder 

 of a steam-engine is necessary for the flames to exert their ex- 

 pansive force, the gas perhaps not instantly igniting on its 

 emergence from the jet; and this "lead" |the mere oscillations 

 of the surrounding air are unable to supply ; but in the 

 position which the jet occupies in the tube, the air-pressures, 

 which return at periods answering to a half stroke of the flame 

 before the oscillations, precipitate its development and enable it 

 to exert its pressures at the proper times. The proportion of 

 lead given to the flame increases as it approaches the middle of 

 the tube, where only the variations of pressure act upon it, while 

 at the lower end of the tube it is commanded entirely, like the 

 air-blast of an organ-pipe, by the oscillations of the air. It is 

 perhaps thus that a wire-gauze flame burning at the foot of a 

 lamp-glass sounds so vociferously, because stationary alternations 

 of pressure in the lower part of the tube cannot affect the 

 transmission of gas throiigh the gauze, while the extensive 

 oscillations there produced have perfectly free action in extin- 

 guishing and replenishing the flame. By using a piece 

 of thin glass connecting-tube about 4 ft. long, held ver- 

 tically over an unlighted Bunsen jet, on ligliting the gas 

 escaping at the top, and carefully raising the tube so as to allow 

 the flame to descend very slowly, it may be made to pause in its 

 descent at the successive ventral points corresponding to the har- 

 monic divisions of the tube, sounding the note of the section of 

 the tube above it as it comes to each point of rest. On lowering 

 the tube it ascends, stopping and singing at some higher point of 

 rest, depending apparently upon the less instantaneous inflamma- 

 bility of the gas. With some difficulty, and by shielding the 

 lower end of the tube as much as possible from draughts, the 

 flame was sometimes made to drop quickly within a few inches 

 of the bottom of the tube, stopping always at the same place and 

 sounding there for a moment the lowest note of the tube, when 

 by the strength of its vibrations it was either rapidly extinguished, 

 or else lighted the Bunsen lamp below. The notes sounded by 

 these means were, liowever, not nearly so loud and effective as 

 those obtained when the gas-flame %\'as held at its stationary 

 points by making it come to rest upon wire-gauze. 



I am indebted for almost all of the foregoing experiments to 

 Mr. llaigh, who was very skilful in suggesting and devising 

 modifications of them, leading to the immediate conclusions re- 

 garding the mode of their production to which they appear most 

 distinctly to conduct. Other occupations have hitherto prevented 

 me from attempting to extend and to examine them as thoroughly 

 as they seem to deserve ; but the field of research presented by 

 the study of harmonic flames does not yet appear to be nearly 

 exhausted, and the repetition of the above experiments by 

 others will perhaps throw more light upon the doubtful questions 

 with which they are stdl to some extent surrounded, enabling, 

 it may be, the many significant and easily-recognised features 

 of singing flames to be produced with even more than their 

 present ease and certainty. A. S. Herschel 



SCIENTIFIC SERIALS 



The Cwloi^kal Magazine, July. — In this number Mr. J. CroU 

 commences an article On the physical cause of the submergence 

 and emergence of land during the glacial epoch, which is to be 

 continued. As far as it goes it is concerned with the conceptions 

 we have of the thickness of continental ice. An attempt is made 

 to estimate the thickness of the great antarctic ice-cap, about 

 which " observation and experience to a great extent may be 

 said to be a perfect blank." The condition of the interior of the 

 antarctic continent is inferred from the little that we know of 

 Greenland. The diameter of the ice-cap being taken at 2,Soo, 

 the thickness at the centre is given at the lowest at 6 miles, 

 reckoning a quarter of a degree only as the slope of the upper 

 surface. Mr. Hopkins has recorded that he found one degree the 

 least slope on which ice will move. An ice-cap of only 6 miles 

 in thickness is to many an unfamiliar idea, and "few things," 

 Mr. CroU writes, "have tended more to mislead geologists in 

 the interpretation of glacial phenomena than inadequate concep- 

 tions regarding the magnitude ol continental ice." — The other 

 original articles are On the dawn and development of life on the 



earth, by 11. Woodward, F.R.S.— Notes on carboniferous niono- 

 myaria, by R. Etheridge, jun. — The geology of the Nottingham 

 district, by Rev. A. Irving. — There are two letters on the glacia- 

 tion of the south-west of England, by Dr. Mackintosh and H. B. 

 Woodward. — Mr. Mallet writes that he does not see how he can 

 be charged with "misapprehending" Mr. Scrope in the discus- 

 sion on the nature of volcanic heat, and asks that as he has 

 reduced his own views to clear definition (Phil. Trans., vol. i. 

 1S73) Mr. Scrope will do the same. 



Bulletin de V Aeadcmie Royale des Seienees, &^e., de Relgique, 

 No. 5. — M. Van Beneden contributes the first part (65 pp. in 

 length) of a paper entitled " On the original distinction between 

 the testicle and the ovary ; the sexual character of the two pri- 

 morial layers of the embryo ; the morphological hermaphrodism 

 of an entire 'individual' ; an essay on the theoiy of fecundation." 

 The " essay " opens with an introduction in which reference is 

 made to Huxley's first pointing out that the organism of Zoo- 

 phytes, Medusida?, Polyps, Siphonophora and Hydroidese con- 

 sists essentially of two layers, endoderm and ectoderm, and also 

 to other writers who have studied the relationships of endoderm 

 and ectoderm in various aspects. The second part contains the 

 history and bibliography of the subject, and the third (50 pp. 

 long) describes the author's researches on Hydraeiinia eehiuata, 

 made during a lengthened visit to Ostend. He first describes 

 the characters which the male and female reproductive zooids 

 have in common, and carefully details his methods of prepara- 

 tion. The microscopic description of the female and then of the 

 male zooids or gonosomes is given in much detail, illustrated by 

 plates. He arrives at the following conclusions : — The ovaries 

 are developed entirely from the epithelial Layer of the endoderm. 

 Up to the time of maturity they remain entirely surrounded by 

 the elements of the endoderm. The testicle and spermatozoa 

 are developed from tlie ectoderm. The female sporosacs contain 

 rudimentary testicular organs, and male sporosacs a rudimentary 

 ovary. From a sexual point of view the ectoderm and endoderm 

 have an opposite signification. If it is true that special organs 

 have resulted from specialisation of function following division 

 of labour, then we must believe that originally the whole ecto- 

 derm performed the male sexual function and the endoderm the 

 female. The ectoderm is the animal and male layer, the endo- 

 derm the vegetation and female. Fecundation consists in the 

 union of an egg, the product of the endoderm, with the product 

 of the ectoderm, which brings chemical compounds of "opposite 

 polarity " into union. The new individual is formed at the in- 

 slant the elements of " opposite polarity" unite just as a mole- 

 cule of water is formed by tlie union of atoms of hydrogen and 

 an atom of oxygen. — M. Henry contributes papers on chloral 

 and chlor-ethylic ethers, &c. — M. F. Plateau has sent in a com- 

 munication on the digestion of insects, which is to be published 

 in the memoirs. 



Bulletin de la Soeia/ ifAnthropoloqie de Paris, t. vii. — In the 

 seventh volume of this journal M. Hamy gives us the results of his 

 examination of M. Janneau's officially conducted investigations 

 into the anthropology of Cambodia. He begins by endeavour- 

 ing to define the meaning attached to the three words, "Moi," 

 "Kha," and "Penang," which have hitherto beea used in 

 Annamite, Laolian, and Kmer almost indiscriminately to indi- 

 cate the wild tribes of the hills. By the first of these we must 

 understand the negro tribes occupying the oriental chain of the 

 Cambodian range ; in the second a people not unlike the yellow- 

 races of Laos ; and in the third the tribes in whom the flat-faced 

 non-Caucasian type is strongly marked. The Cambodians 

 themselves distinguish between races, known as Kuoi, who, 

 they say, are the primitive people of the land but not savages, 

 and the Rode, the former being employed in the extraction of 

 the ores of Kompong Svai, and the latter in the breeding and 

 care of horses, while both are exempt from the yoke of slavery 

 which presses heavily upon nearly all the other tribes. In the Cam- 

 bodian language M. Janneau thinks he can trace evidence of 

 identity with many of the primitive forms of the roots of the 

 mother-tongue of the Indo-European languages. The Aryan name 

 " Rama" appears among the ancient regal titles of Cambodia, 

 and while the Sanscrit "Ramayana " includes the Cambodians 

 amongst the offspring of the immaculate cow. Cabala, the 

 people themselves have from the most remote antiquity 

 made the cow the object of special adoration. — The ques- 

 tion of the depopulation of certain districts, more especially in 

 the Polynesian and other Australasian insular groups, has lately 

 attracted especial attention among the members of the Anthro- 

 pological Society of Paris. The Gambier Islands, which in 



