Jan. 1 6, 1879] 



NATURE 



259 



Koitapu are supposed to have power to bewitch and cause 

 disease, also to prevent rain from falling. 



The Motu take presents to Koitapu in case of disease, and 

 tke women sometimes suck the seat of pain in the same manner 

 as described in Sir J. Lubbock's "Origin of Civilisation, pp. 

 27 28 There are many indications that the Koitapu are now 

 but a small remnant of what was once a numerous and powerful 



The Koiari are closely allied to the Koitapu, and inhabit the 

 mountains at the back of the Motu and Koitapu district. They 

 con<;ist of a number of scattered tribes. They are physically 

 inferior to the Motu and Koitapu, but more numerous. They 

 are small in stature, dark in colour, and dirty in person. Their 

 hands and feet are remarkably small. Their villages are bmlt 

 on the ridge of a hill. Tree houses are common, almost every 

 village having one at a considerable height. Their language is 

 simifar to Koitapu, They cultivate the soil carefully, and are 

 great hunters. The women are more degraded than among 

 the KoiUpu or Motu, and polygamy is more common. 



The dead are laid out for some weeks in the house, and then 

 exposed to sun and smoke until perfectly dry. When the 

 bones fall apart they are collected and tied up in a bundle and 

 hung up in the deserted house or in a tree close by. 



The mode of salutation among the Koiari is peculiar. They 

 salute their friends by chucking them under the chin. 



They are great chewers of the betel-nut, and are very eager 

 to obtain salt. They barter their produce occasionally with the 

 Motu at Port Moresby for fish, cocoa-nuts, salt, and pottery. 



1 



SCIENTIFIC SERIALS 

 Annalen der Physik und Chemie, No. il, 1878.— In a valuable 

 paper oa the passage of the galvanic ctirrent through iron, Herr 

 Auerbach describes experiments with reference to the effect of 

 longitudinal magnetisation of iron bars or wires on their 

 resistance, and to the extra currents at closing and opening of 

 the circuit, explained by a transverse or circular magnetisation. 

 Circularly magnetic iron conducts a current worse, the stronger 

 the circular magnetisation. The resistance of longitudinally 

 magnetised iron may be less or greater than that of unmagnetic ; 

 in the former case the resistance -function has nowhere a 

 minimum or maximum ; the resistance rises steadily from the 

 state of saturated longitudinal, to that of saturated circular, 

 magnetism ; and this is reali-:ed in hard steel. In the other case 

 the resistance-function has a minimum for the unmagnetic state, 

 Herr Auerbach explains the efifects observed on the hypothesis 

 of rotatable molecular magnets, and indicates the bearing of his 

 views on them on the fundamental laws of galvanism, and the 

 galvanic constants of iron. — In a third series of experimental 

 magnetic researches, Herr Fromme deals with two modes of 

 magnetising a rod with a spiral conveying a galvanic current. 

 It may be inserted in the spiral after the circuit has been com- 

 pleted, and withdrawn while the current is still flowing ; or it 

 may be inserted before the circuit is closed, and withdrawn after 

 it is opened. He now obtains a distinct difference, unperceived 

 before, between the efiects, and the causes of the phenomena 

 are thought to be not of secondary nature (or very little so), but 

 deducible from the essence of magnetism. The results of 

 experiment are found to agree better with the Neumann-Kirch- 

 hoff theory, when the latter of the two above methods is aban- 

 doned. — Herr Ritter communicates a first paper of researches 

 on the height of the atmosphere, and the constitution of gaseous 

 cosmical substances. On the two hypotheses of an indifferent 

 state of equilibrium in the atmosphere, and of the oxygen and 

 nitrogen retaining approximately, in all changes of condition, 

 the properties of a so-called perfect gas, he arrives theoretically 

 at a height of 40 km. for the atmosphere, whereas Schiaparelli's 

 observations make it more than 200 km. He removes this dis- 

 crepancy by supposing that, in the rise of the air-masses, not 

 only aqueous vapour, but oxygen and nitrogen, pass into the 

 state of agijregati^n of a snow-cloud. — Dr. Kolacek studies 

 mathematically the influence of capillary surface-pressure on the 

 velocity of propagation of water-waves. 



SOCIETIES AND ACADEMIES 



London 



Royal Society, January 9. — "Note on the Inequalities of 



the Diurnal Range of the Declination Magnet as recorded at the 



Kew Observatory," by Balfour Stewart, F.R.S., Professor of 



Natural Philosophy in Owens College, Manchester, and Willianri 

 Dodgson. 



We are at present engaged in searching for the natural ir.- 

 equalities of the above range, more especially for any of which 

 the period is between 24 and 25 days. We find strong evidence 

 of an inequality of considerable magnitude of which the period 

 is 24*00 days, very nearly. We have also found preliminary 

 evidence of the existence of two considerable inequalities having 

 periods not very far from 24*65 and 24*80 days. These two 

 appear to come together in about 1 1 years, but we cannot yet 

 give the exact time of this. 



We have not found a trace of any inequality vnih a period of 

 24*25 days, 



" Some Experiments on Metallic Reflexion," by Sir John 

 Conroy, Bart., M.A, Communicated by Prof. G. G. Stokes, 

 Sec. R,S, 



He finds that when light is reflected from a polished surface 

 of gold or copper in contact with various media, the angle of 

 principal incidence diminishes, and the principal azimuth in- 

 creases with the increase of the refractive index of the inedium 

 in contact with the metallic surface ; and further, the diminution 

 in the value of the principal incidence appears to be nearly in 

 proportion to the increase of the refractive index of the surround- 

 ing medium. 



He states that theS^values of these angles for gold with red 

 light are : — 



Principal 

 Incidence. 



Priadpal 

 Anmuth. 



In air 760 35 27 



In water 72 46 36 23 



In carbon bisulphide 7003 3^4^ 



Assuming that the angle of principal incidence for a metal is the 

 same as the angle of polarisation of a transparent substance, 

 that is the angle whose tangent is equal to the refractive index, 

 the value of that angle in air, as deduced from the measurements 

 made in water and carbon bisulphide by multiplying the tangent 

 of the principal incidence in those media by their refractive 

 indices is 76*53 and 77*22 instead of 76. 



" Researches on the Absorption of the Ultra-Violet Rays of 

 the Spectrum by Organic Substances," by W. N. Hartley, 

 F.Inst. Chem., F.R.S.E., F.C.S,, Demonstrator of Chemistrj-, 

 King's College, London, and A, K. Huntington, F.Inst. Chem., 

 A.R.Sc. Mines, F.C.S. Communicated by Prof. G. G. Stokes, 

 Sec.R.S. 



The following were the conclusions reached : — 



1. The normal alcohols of the series C„H2n + lOH are remark- 

 able for transparency to the ultra-violet rays of the spectrum, 

 pure methylic alcohol being as nearly so as water. 



2. The normal fatty acids exhibit a greater absorption of the 

 more refrangible rays of the ultra-violet spectrum than the 

 normal alcohols containing the same number of carbon-atoms. 



3. There is an increased absorption of the more refrangible 

 rays corresponding to each increment of CH2 in the molecule of 

 the alcohols and acids. 



4. Like the alcohols and acids, the ethereal salts derived from 

 them are highly transparent to the ultra-violet rays, and do not 

 exhibit absorption-bands. 



In order to ascertain whether isomeric bodies exhibited similar 

 or identical absorption-spectra, a series of benzene derivatives 

 was examined. From the great absorptive power of this class 

 of substances it was found necessary to use very dilute solutions, 

 even though the cells holding the liquids were not more than 

 o*75 inch in thickness. Curves were plotted by taking the pro- 

 portions of substances in solution as ordinate?, and the position 

 of absorption-bands as abscissae, and these curves are highly 

 characteristic features of very many compounds. About twenty 

 diagrams hav« thus been made. 



The following is a summary of the chief points of interest 

 appertaining to benzene and its derivatives : — 



1. Benzene, and the hydrocarbons, the phenols, acids, and 

 amines derived therefrom, are remarkable firstly, for their 

 powerful absorption of the ultra-violet rays ; secondly, for the 

 absorption-bands made visible by dissolving them in water or 

 alcohol, and diltiting ; and thirdly, for the extraordinary intensity 

 of these absorption-bands, that is to say, their power of resisting 

 dilution. 



2. Isomeric bodies, containing the benzene nucleus, exhibit 

 widely different spectra, inasmuch as their absorption-bands 

 vary in position and in intensity. 



