Jtdy lo, 1879] 



NATURE 



259 



mainland of Asia, may have been derived from the same stock, 

 but the special interest of the Andamanese consists in the fact 

 that they alone of the diminutive black, woolly-haired people, 

 occupy the whole of the small islands, on which their ancestors 

 have dwelt from time immemorial, or rather did so occupy them 

 until the coming upon them of the English in 1857. The ma- 

 terials upon which the observations contained in tlie memoir are 

 based, are far more complete than any whch have hitherto teen 

 brought together, consisting of nineteen skeletons and nearly thirty 

 skulls. The skeletons indicate an average height of 4 feet 9 inches 

 in the males, and 4 feet 6 inches in the females, thus showing that 

 they belong to some of the smallest of known races. The skulls 

 all belong to what is known as the brachycephalic or round- 

 headed type, having an average cephalic index (or proportion of 

 breadth to length) of 82. The forehead is broad and flat, with- 

 out any projection over the orbits. The nose is narrow and the 

 jaws less prominent than in the other black races. The propor- 

 tionate length of the various bones of the limbs differ greatly 

 from the European standard, but resemble those of the negro. 

 With the Australian the Andamanese have very little affinity, 

 the smooth hair of the former entirely separating them, inde- 

 pendently of cranial characters, as dolichocephaly (or long- 

 headedness) strongly pronounced brow ridges, low orbital index, 

 wide nasal aperture, great prognathism, &c. It is to the other 

 wooliy-haired races that we must naturally turn in endeavouring 

 to find their nearest relatives. The Papuans and inhabitants of 

 the Melanesian Islands differ from them greatly in their principal 

 cranial characters, especially in the great height and narrowness 

 of the skull. The Tasmanians had wider heads, but their facial 

 characters were more like those of the Australians, and therefore 

 widely different from the Andamanese. The African negroes, again, 

 are almost all dolichocephalic, and as a general rule are extremely 

 prognathous, and strongly platyrhine or broad-nosed. Many of 

 them, however, have the smooth brow and round orbits seen in 

 the Andamanese, and not generally met with in the true oceanic 

 negroes. The natives of the Andaman Islands, with whom 

 may probably be associated the less known Aetas of the 

 Philippines, the Semangs of the Malay Peninsula, thus constitute 

 a race apart, to which the name Negrito may properly be 

 applied. At first sight, they appear m their craniological 

 characters to present little affinity to either of the otiier woolly- 

 haired races, but it is probable that they represent a small or 

 infantile type of the same primary group, as nearly all the 

 characters by which they differ from the other negroes — the 

 smaller size, smoother, and more globular heads, absence of 

 supraorbital prominences, rounder orbits, and less projecting 

 jaws, are those which we find in the younger individuals of a 

 species, as compared with the older, or in the smaller species of 

 a natural group as compared with the larger. It is veiy possible, 

 but this is purely hypothetical, that the Andamanese, whose 

 geographical position is almost midway between either extremes 

 of the range of the woolly-haired races, may be the unchanged or 

 little-modified representatives of a primitive type, from which the 

 African negroes on the one hand, and the Oceanic negroes on 

 the other, have taken their origin, and hence everything con- 

 nected with their history or structure becomes of the greatest 

 interest to the anthropologists. — The following papers were 

 also read : — On paleolithic implements from the Valley of the 

 Brent, by Mr. Worthington G. Smith ; and Portstewart and other 

 flint factories of the north of Ireland, by W. J. Knowles. 



Physical Society, June 21.— An extra meeting of this So- 

 ciety was held on the above date at Cooper's Hill Indian Engi- 

 neering College, on the invitation of Col. Chesney, R.E., Lord 

 Kosse occupying the chair.— Prof. Unwin, of the College, read 

 a paper on experiments relating to the friction of fluids on solid 

 surfaces against which they rub. It has long been known that 

 a board dragged through water suffers a resistance varying in 

 some way as the square of the velocity ; that a stream takes a 

 uniform motion at such a velocity that the component of the 

 weight of the water down its inclined bed is balanced by the 

 frictional drag on the bottom. The fluid in the neighbourhood 

 of the stream is known not to move as a solid mass, the centre 

 moving faster than the sides, and the different fluid layers rub 

 against each other. The adhesion of the fluid to the solid 

 against which it moves also gives rise to a sliding or rubbing 

 action. Our knowledge of the subject has hitherto been gained 

 from observations on pipes streams, and from the experiments 

 of the late Mr. FroTide with a plank of wood drawn through 

 the water of a canal. It is desirable to have a set of laboratory 

 experiments, however, in which the conditions can be varied more 



than can be done by such methods, and for this purpose the 

 author had designed a special apparatus. In Mr. Froude's ex- 

 periments there was a practically unlimited mass of water and a 

 definitely limited extent of solid surface, and his results are not 

 free from certain anomalies. The author thought it might be 

 instructive to try the other case of a limited mass of water and 

 a virtually unlimited surface. A disk in rotation gives such a 

 surface. In some respects a cylinder would (as suggested by 

 Prof. Ayrton) be the simplest to treat theoretically, but there 

 are experimental difficulties in its way. The apparatus of the 

 author consists of a metal disk rotated on a vertical axis in a 

 vessel of water, and the problem is to de termine its resistance to 

 rotation, since this will be equivalent to the water-friction upon 

 it. Within the outer vessel is placed a thin copper chamber, 

 the diameter of which is unalterable, but the depth is variable 

 at pleasure. The disk is placed concentrically inside this cham- 

 ber, where there are two cheese-shaped masses of water, one 

 above and one below the disk, which are dragged into rota- 

 tion next the disk, and retarded next the sides of the pan. 

 The couple required to rotate the disks is equal to the couple 

 exerted by' the disk or the fluid when the motion is uniform ; hence 

 the tendency of the chamber to rotate is measured, by suspending 

 the latter from three wires in a manner similar to the bifilar 

 suspension of magnets. An index marks whether it rotates or 

 not on a graduated scale ; and a weight suspended by a cord 

 measures the force required to keep the index at zero. Let M 

 be the moment of the frictional resistance of the disk, A'' the 

 number of revolutions per second. Then M — C N'^, where C 

 and X are constants. The author has obtained a number of 

 results which are, however, not yet ready for publication. He 

 mentioned, however, that a rough cast-iron disk has a frictional 

 resistance almost exactly as the square of the velocity, whereas a 

 turned brass disk gave a value of x decidedly less than 2. The 

 resistance is a little greater when the mass of water is larger. 

 These results were calculated for a speed of 10 feet per second. 

 The author hopes to try the effect of temperature, &c., on fluid 

 friction and viscous" as well as thin fluids. Prof. Unwin also 

 exhibited a piece of apparatus with which he hopes to study the 

 stress of rivetted plates under shear, by means of elastic sub- 

 stances such as caoutchouc. He purposes to stretch the caout- 

 chouc and photograph the appearance of stress rivetted lines upon 

 it. — Lieut. G. S. Clark, R.E., explained the process invented 

 by Prof. McLeod and himself for determining the absolute pitch 

 of tuning-forks. Unlike other methods this is an optical one, and 

 consists in arranging the tuning-fork to vibrate in front of a 

 rotating drum whose periphery is marked with dots or fine lines 

 at equal intervals. A microscope was arranged to comprise in 

 its field of view the edge of the fork and several of the intervals on 

 the drum, so that when the drum was rotated at a rate which made 

 the speed of an interval equal to the period of the fork, a set of pro- 

 minences or waves, in width equal to an interval, were visible ; 

 the body of the wave being caused by the advance and recession 

 of the fork in its vibration. The rotation of the drum was 

 regulated by an air-regulator devised by Prof. Unwin, the 

 observer himself quickening or slowing the dram so as to keep 

 the* prominences steady. The time Was beat by an electric clock 

 designed by Prof. McLeod. An aniline glass pen was used to 

 mark the beginning and end of the period of observation on the 

 drum. A counter was also employed to give the number of revo- 

 lutions. The pen and counter were actuated by electricity through 

 the medium of a key. In these experiments a Konig fork giving 

 256 vibrations per second correct at i6°'i C, was tested, and 

 found to give 256"2966 vibrations per second. Frequent bowing 

 did not alter the phase. Fixing the fork rigidly, as in a vice, 

 did so. The temperature coefficient for Konig's forks (•0001 1 

 for each degree Centigrade) was confirmed by these experiments. 

 Forks of different octaves were compared ; audible beats could 

 be counted, and modifications of Lesage's figures seen. This 

 optical method is preferable to audible ones, because of its inde- 

 pendence of the ear and the fact that nothing is attached to the 

 fork itself. Prof. Guthrie inquired if the periods of the forks 

 had been found to alter through u?e or magnetisation. Tlie 

 author said that he had not yet tested these points. Pr^f. McLeod 

 instanced an old Kbnig fork which was correct at l6°'l C, 

 requiring now a temperature of 25° C. to make it so. Lord 

 Rosse suggested the use of the regulators employed with equa- 

 torial clocks to keep the rotation of the drum steady. Capt. 

 Abney inquired if a difference of vibration had been detected 

 between the beginning and end of a series of observations. None 

 had been certainly observed. — Prof. Macleod then described an 

 electric clock used in the foregoing experiments. The zinc and 



