The period of existence succeeding the very red stars has illustrations near at hand, we think, in Jupiter, Saturn, Uranus and Neptune, and in the Earth and the other small planets and the Moon: bodies which still contain much heat, but which are invisible save by means of reflected light.
The progression of stellar development, which we have described, has been based upon the radiation of heat. This is necessarily gradual, and the corresponding changes of spectrum should likewise be gradual and continuous. It is not intended to give the impression that only a few types of spectra are in evidence: the variety is very great. The labels, Class B, Class A, and so on to Class N, are intended to mark the miles in the evolutionary journey. The Harvard experts have put up other labels to mark the tenths of miles, so to speak, and some day we shall expect to see the hundredths labeled. Further, it is not here proposed that heat radiation is the only vital factor in the processes of evolution. The mass of a star may be an important item, and the electrical conditions may be concerned. A very small star and a very massive star may develop differently, and it is conceivable that there may be actual differences of composition. But heat-radiation is doubtless the most important factor.
The evolutionary processes must proceed with extreme deliberation. The radiation of the heat actually present at any moment in a large helium star would probably not require many tens of thousands of years, but this quantity of heat is negligible in comparison with the quantity generated within the star during and by the processes of condensation from the helium age down to the Class M state. We know that the compression of any body against resistance generates or releases heat. Now a gaseous star at any instant is in a state of equilibrium. Its internal heat and the centrifugal force due to its rotation about an axis are trying to expand it. Its own gravitational power is trying to draw all of its materials to the center. Until there is a loss of heat no contraction can occur; but just as soon as there is such a loss gravity proceeds to diminish the stellar volume. Contraction will proceed more slowly than we should at first thought expect, because in the process of contraction additional heat is generated and this becomes a factor in resisting further compression. Contraction is resisted vastly more by the heat generated in the process of contraction than it is by the store of heat already in evidence. The quantity of heat in our Sun, now existing as heat, would suffice to maintain its present rate of outflow only a few thousands of years. The heat generated in the process of the Sun's shrinkage under gravity, however, is so extensive as to maintain the supply during millions of years to come. Helmholtz has shown that the reduction of the Sun's radius at the rate of 45 meters per year would generate as much heat within the Sun as is now radiated. This rate of shrinkage is so slow that our most refined instruments could not detect a change in the solar diameter until after the lapse of 4,000 or 5,000 years. Again, there are reasons for suspecting that the processes of evolution in our Sun, and in other stars as well, may be enormously prolonged through the influence of energy within the atoms or molecules of matter composing them. The subatomic forces residing in the radioactive elements represent the most condensed form of energy of which we have any conception. It is believed that the subatomic energy in a mass of radium is at least a million-fold greater than the energy represented in the combustion or other chemical transformation of any ordinary substance having the same mass. These radioactive forces are released with extreme slowness, in the form of heat or the equivalent; and if these substances exist moderately in the Sun and stars, as they do in the Earth, they may well be important factors in prolonging the lives of these bodies.
Speaking somewhat loosely, I think we may say that the processes of evolution from an extended nebula to a condensed nebula and from the latter to a spherical star, are comparatively rapid, perhaps normally confined to a few tens of millions of years; but that the further we proceed in the development process, from the blue star to the yellow, and possibly but not certainly on to the red star, the slower is the progress made, for the radiating surface through which all the energy from the interior must pass becomes smaller and smaller in proportion to the mass, and the convection currents which carry heat from the interior to the surface must slow down in speed.
A HISTORY OF FIJI.
BY DR. ALFRED GOLDSBOROUGH MAYER
IV
THE Fijians had a well-organized social system which recognized six classes of society. (1) Kings and queens (Tuis and Andis). (2) Chiefs of districts (Rokos). (3) Chiefs of villages, priests (Betes), and land owners (Mata-ni-vanuas). (4) Distinguished warriors of low birth, chiefs of the carpenter caste (Rokolas), and chiefs of the turtle fishermen. (5) Common people (Kai-si). (6) Slaves taken in battle.
The high chiefs still inspire great respect, and indeed it has been the policy of the British government to maintain a large measure of their former authority. Thus of the 17 provinces into which the group was divided, 11 are governed by high chiefs entitled Roko Tui, and there are about 176 inferior chiefs who are the head men of districts, and 31 native magistrates. In so far as may be consistent with order and civilization these chiefs are permitted to govern in the old paternal manner, and they are veritably patriarchs of their people. The district chiefs are still elected by the land owners, mata-ni-vanuas, by a showing of hands as of old.
Independent of respect paid to those in authority, rank is still reverenced in Fiji. Once acting under the kind permission and advice of our generous friend Mr. Allardyce, the colonial secretary, and accompanied by my ship-mates Drs. Charles H. Townsend, and H. F. Moore, I went upon a journey of some days into the interior of Viti Levu, our guide and companion being Ratu Pope Seniloli, a grandson of king Thakombau, and one of the high chiefs of Mbau. Upon meeting Ratu Pope every native dropped his burdens, stepped to the side of the wood-path and crouched down, softly chanting the words of the tame, muduo! wo! No one ever stepped upon his shadow, and if desirous of crossing his path they passed in front, never behind him. Clubs were lowered in his presence, and no man stood fully erect when he was near. The very language addressed to high chiefs is different from that used in conversation between ordinary men, these customs being such that the inferior places himself in a defenceless position with respect to his superior.