502 



NATURE 



[September 22, 1892 



makes it quite hot. Moreover, the tremor of the whirling 

 machine, in which some four or five horse-power is sometimes 

 being expended, is but too liable to communicate itself to the op- 

 tical part of the apparatus. Of course elaborate precautions are 

 taken against this. Although the two parts, the mechanical 

 and the optical, are so close together, their supports are entirely 

 independent. But they have to rest on the same earth, and 

 hence communicated tremors are not absent. They are the 

 cause of all the slight residual trouble. 



The method of observation now consists in setting a wire 

 of the micrometer accurately in the centre of the middle band, 

 while another wire is usually set on the first band to the left. 

 Then the micrometer heads are read, and the setting repeated 

 once or twice to see how closely and dependably they can be 

 set in the same position. Then we begin to spin the disks, and 

 when they are going at some high speed, measured by a siren 

 note and in other ways, the micrometer wires are reset and read 

 — reset several times and read each time. Then the disks are 

 stopped and more readings are taken. Then their motion is 

 reversed, the wires set and read again ; and finally the motion 

 is once more stopped and another set of readings taken. By 

 this means the absolute shift of middle band and its relative 

 interpretation in terms of wave-length are simultaneously ob- 

 tained ; for the distance from the one wire to the other, which 

 is often two revolutions of a micrometer head, represents a whole 

 wave-length shift. 



In the best experiments I do still often see something like a 

 fiftieth of a band shift, but it is caused by residual spurious 

 causes, for it repeats itself with sufficient accuracy in the same 

 direction when the disks are spun the other way round. 



Of real reversible shift, due to motion of the ether, I see 

 nothing. I do not believe the ether moves. It does not move 

 at a five-hundredth part of the speed of the steel disks. I hope 

 to go further, but my conclusion so far is that such things as 

 circular-saws, flywheels, railway trains, and all ordinary masses 

 of matter do not appreciably carry the ether with them. Their 

 motion does not seem to disturb it in the least. 



The presumption is that the same is true for the earth ; but the 

 earth is a big body, it is conceivable that so great a mass may be 

 able to act when a small mass would fail. I would not like to 

 be too sure about the earth. What I d6 feel already pretty sure 

 of is that if moving matter disturbs ether in its neighbourhood 

 at all, it does so by some minute action, comparable in amount 

 perhaps to gravitation, and possibly by means of the same pro- 

 perty as that to which gravitation is due — not by anything that 

 can fairly be likened to ethereal viscosity. 



NATIVE NEW ZEALAND BIRDS. 

 "pROM a scientific point of view it is of so much importance 

 that native New Zealand birds should be protected that 

 many naturalists will read with interest the following memoran- 

 dum, which was drawn up by Lord Onslow, the late Governor 

 of New Zealand, and presented to both Houses of the General 

 Assembly by command of his Excellency : — 



It is admitted by naturalists that New Zealand possesses in 

 some respects the most interesting avifauna in the world. It is 

 a melancholy fact that, under the changed condition of exis- 

 tence this remarkable avifauna is passing away. Some of the 

 species have already disappeared, whilst others are verging on 

 extinction. Take, for example, the wingless birds of New 

 Zealand. These diminutive representatives of the gigantic 

 brevipennate birds which formerly inhabited New Zealand 

 are objects of the highest interest to the natural historian. The 

 kiwis, like their colossal prototypes the moas, once existed in 

 very considerable numbers in almost every part of the country. 

 At the time of the first colonization of New Zealand, fifty years 

 ago, they were still abundant in all suitable localities. At the 

 present day their last refuges may be indicated on the map 

 without any difficulty. The North Island species (Apteryx 

 btiUeri) is still comparatively plentiful in the wooded heights of 

 Pirongia and in the bosky groves of the Upper Wanganui. 

 From all other localities where formerly numerous it has prac- 

 tically disappeared. The South Island kiwi (Apieryx australis) 

 is now met with in only widely-scattered localities on the west 

 coast. The small spotted or grey kiwi {Apteryx oweni), of 

 which perhaps thousands could have been obtained a few years 

 back, has succumbed to the ravages of the stoat and weasel, 

 the persecution by wild dogs, and the necessities of roving 



NO. II 95. VOL. 46] 



diggers, and it is only now to be found in any number along the 

 lower wooded ranges of the Southern Alps. Apteryx haasti is 

 one of our rarest species, and Apteryx maxima is strictly con- 

 fined to the wooded parts of Stewart Island. 



The kakapo, or ground-parrot {Striugops habroptilus), which 

 was formerly so abundant in the wooded country along the 

 whole of the West Coast Sounds and on the western slope of 

 the Southern Alps, is becoming a scarce bird. According to 

 Mr. Richardson, who recently read an exhaustive paper on the 

 subject before the Otago Institute, both the kiwi and the 

 kakapo are now confined to very restricted districts, within 

 which, under the combined attacks of introduced wild dogs and 

 cats, stoats, weasels, and ferrets, they are fast diminishing. 



The blue-wattled crow and South Island thrush, which were 

 every-day camp-visitors when Sir James Hector explored the 

 West Coast in 1863, are now very rarely seen ; whilst in the 

 North Island the native thrush and some of the smaller birds 

 have disappeared altogether. 



Prominent writers on zoological science, such as Prof. 

 Newton, of Cambridge, Prof. Flower, at the head of the British 

 Museum, and Dr. Sclater, the accomplished secretary of the 

 Zoological Society of London, have over and over again urged 

 the importance of some steps being taken for the conservation 

 of New Zealand birds ; and they have pointed out that it will 

 be a lasting reproach to the present generation of colonists if 

 no attempt is made to save some — if only a remnant — of these 

 expiring forms for the student of the future. Thus, Prof 

 Newton, in his address to the Biological Section of the British 

 Association, at Manchester, in 1887, saith : "I would ask you 

 to bear in mind that these indigenous species of New Zealand 

 are, with scarcely an exception, peculiar to the country, and, 

 from every scientific point of view, of the most instructive 

 character. They supply a link with the past that, once lost, 

 can never be recovered. It is therefore incumbent upon us to 

 know all we can about them before they vanish. . . . The 

 forms we are allowing to be killed off, being almost without ex- 

 ception ancient forms, are just those that will teach us more of 

 the way in which life has spread over the globe than any other 

 recent forms ; and for the sake of posterity, as well as to escape 

 its reproach, we ought to learn all we can about them before 

 they go hence and are no more seen." 



The chief cause of the destruction of native birds is no doubt 

 the introduction of foreign animals, against which the indigenous 

 species are unable to contend successfully in the struggle for 

 existence, especially under the changed conditions of life brought 

 about by colonization. Probably the chief factor in this work 

 of destruction is the Norway rat, whose introduction was of 

 course unintentional, but an inevitable incident of settlement. 

 The insectivorous and other birds introduced (whether wisely or 

 not it is not necessary now to discuss) by our various acclimati- 

 zation societies have, as it were, driven out and replaced many 

 of the native species. These latter have succumbed to some 

 general law of nature under which races of animals and plants 

 yield to foreign invasion and rapidly disappear, the aboriginal 

 races of man being no exception to this general rule. Where 

 the causes themselves are recondite, it is, of course, difficult to 

 find the means of counteracting them ; but it is an observed law 

 of nature that expiring races survive and linger longest in insular 

 areas. That has been the experience of zoologists all over the 

 world, the islands of Mauritius and Rodriguez presenting a 

 striking instance in point. Here in New Zealand we have many 

 similar evidences. The remarkable tuatara lizard {Sphenodon 

 punctatum), supposed to be a survival from a very ancient 

 fauna, and constituting, per se, a distinct order of reptilia, which 

 years ago became extinct on the mainland (chiefly through the 

 ravages of introduced wild pigs), still exists in very considerable 

 numbers on the small islands lying off our coasts. The mako- 

 mako, or bell-bird {Anthornis me/anura), at one time the very 

 commonest of our birds, although still plentiful in the South 

 Island, has absolutely disappeared from every part of the North 

 Island, but it still exists on the wooded islands of the Hauraki 

 Gulf and Bay of Plenty, and on the island of Kapiti, in Cook 

 Strait. The same remarks apply with almost equal force to the 

 wood-robin [Miro albifrons) and the white-head (Clitonyx 

 albicapilla), two species which have never inhabited 

 the South Island at all. The stitch-bird {Pogonornis 

 cincta), which forms a sort of connecting link with the 

 avifauna of Australia, was thirty years ago very plentiful in the 

 woods surrounding Wellington, but it had long before dis- 

 appeared from the northern parts of the island. It is now 



