370 



NATURE 



[August 14, 1590 



separate breeding is long continued, incompatibility in all these 

 respects tends gradually to arise ; but it is manifest that incom- 

 patibility of industrial habits implies diversity in the forms of 

 natural selection that shape each portion. I therefore maintain 

 that separation which necessarily includes the cessation of reflex 

 selection between the portions separated is a cause of segregation 

 and divergence, and that it introduces diversity of natural selec- 

 tion, which is a still further cause of divergence. 



Unless the separated portions of a species possess exactly the 

 same average character (which we must believe is seldom, if 

 ever, the case), separation must, from the first, be more or less 

 segregative ; and even in cases where the portions completely 

 correspond in character (if there are any such cases), the cessation 

 of reflex selection which is involved in the separate breeding, 

 must result in segregration as soon as the power of heredity 

 begins to weaken ; and this is in due time followed by other 

 forms of intensive segregation. I therefore conclude that in- 

 discriminate separation may be regarded as a preliminary form 

 of segregation (i.e. discriminate separation), and that in the 

 nomenclature we ordinarily use both principles may be called 

 " segregation " without confusion. 



26, Concession, Osaka, Japan. John T. Gulick. 



The Affinities of Heliopora cccrulea. 



In Prof. Moseley's admirable account of the structure and 

 affinities of Heliopora, published in the Transactions of the 

 Royal Society, 1876, and afterwards in the Challenger Reports, 

 there occurs the following passage : "... directly the coral [i.e. 

 Heliopora) was left at rest a swarm of a species of Leucodora, 

 closely resembling Letccodora nasuta, which infests the coral and 

 perforates it all over, expanded themselves at once." 



This will probably explain the cause of the curious mistake 

 that Mr. Saville Kent has made, in his letter published in last 

 week's Nature (p. 340), in supposing that Heliopora is a tubi- 

 colous annelid. Heliopora is not a tubicolous annelid, nor does 

 it belong to the " Hydrozoic division of the Coelenterata," but 

 it is, without a shadow of doubt, as Moseley described it to be, 

 an Alcyonarian. 



When I was preparing my paper on the " Siphonoglyphe in the 

 stomodasum of Alcyonarians " in 1883, Prof. Moseley kindly 

 placed at my disposal his preparations of Heliopora, and I was 

 able then fully to confirm his conclusions as to the Alcyonarian 

 nature of this interesting coral. 



During my visits to the coral reefs on the coasts of North 

 Celebes and the adjacent islands, I came across many large and 

 beautiful specimens of Heliopora, some of which I carefully 

 preserved for further investigation at home. I never found the 

 polyps fully expanded with the eight pinnate tentacles standing 

 out from the disk like the petals of a flower, but in the few 

 instances when I saw the polyps protruded \ inch or thereabouts 

 from the surface of the coral the tentacles were partially with- 

 drawn, so that their characteristic features were hidden. 



Since my return from Celebes I have made a large number of 

 sections of the material I brought back with me with a view to 

 the publication of a short paper on some further details of its 

 anatomy, and I have recently been able to supplement this by a 

 series of preparations I have made from the excellent material 

 given to me by Prof. Haddon, who found Heliopora in abun- 

 dance in Torres Straits. 



I will not venture, in the present state of my investigation, to 

 state my opinion as to the position that Heliopora should occupy 

 in the group to which it undoubtedly belongs ; I merely wish to 

 call the attention of the readers of Nature to the fact that its 

 Alcyonarian characters are beyond dispute. 



Downing College, August 9. Sydney J. Hickson. 



Meteors. 



Last night, between 11. 12 and 11.52, I and another observer 

 saw altogether eighty-three meteors, eighty of which were 

 Perseids. Some of them were very brilliant, especially those 

 near the neighbourhood of Aquila. 



The remaining three meteors had different paths, one having 

 a direction exactly opposite to that of the Perseids. 



The other observer was watching the radiant point and the 

 region around it, while I observed the south-west quadrant. 



NO. 1085, VOL. 42] 



More observations would have been ma de, but were in- 

 terrupted by clouds. W. J. LocKYER. 

 Observatory House, Westgate-on-Sea, August 12. 



/ 



A LIQUID COMPOUND OF NICKEL AND 

 CARBON MONOXIDE. 



T N the August number of the Journal of the Chemical 

 -*■ Society a full account is given of the remarkable new 

 compound described by Mr. Mond, in conjunction with 

 Drs. Langer and Quincke, at the last meeting of the 

 Chemical Society. The following is an outline of the 

 main facts described in their communication. 



Carbon monoxide is found to be affected in a very 

 curious manner when passed over finely divided metallic 

 nickel heated to a temperature of 35o°-45o° C. The metal 

 becomes converted into a black amorphous powder con- 

 taining nickel and carbon, the carbon monoxide becoming 

 at the same time changed into the dioxide owing to the 

 loss of carbon. A comparatively small amount of nickel 

 is capable of decomposing a very large quantity of carbon 

 monoxide, and at the commencement of the operation 

 the gas may be passed over at a very rapid rate without 

 any escaping decomposition. As the operation continues, 

 the change becomes less and less complete, but even 

 after numerous repetitions of the experiment carbonic 

 anhydride continues to be formed. The solid product of 

 the reaction appears to vary in composition somewhat 

 widely according to the temperature and the time during 

 virhich the operation is carried on. The highest propor- 

 tion of carbon found was 85 per cent. Some time ago 

 MM. Gautier and Hallopeau obtained a similar product, 

 containing 80 per cent, of carbon, by the action of carbon 

 bisulphide upon metallic nickel. The nickel is only 

 partially removed by acids, for even after repeated ex- 

 traction the whole of the nickel is not found in solution. 



When this black substance was allowed to cool in the 

 current of carbon monoxide another change was found to 

 occur, with production of some volatile substance, whose 

 vapour rendered a non-luminous Bunsen gas flame placed 

 in its path highly luminous. Further, on heating a por- 

 tion of the tube near the exit a mirror of metallic nickel 

 was obtained mixed with a little carbon. Evidently a 

 gaseous substance containing nickel was contained in the 

 issuing gas, a circumstance of considerable importance 

 in view of the non-volatility of the ordinary known com- 

 pounds of nickel. Experiments were then made with the 

 idea of obtaining larger quantities of the new substance 

 and isolating it from the other gaseous products. It was 

 eventually found that when finely divided nickel, obtained 

 by reducing nickel oxide in a current of hydrogen at a 

 temperature of about 400°, is allowed to cool in a slow 

 stream of carbonic oxide, the latter gas is very readily 

 absorbed as soon as the temperature has fallen to about 

 100°. If the current of carbon monoxide is continued, 

 or if that gas is replaced by an inert gas, such as carbon 

 dioxide, nitrogen, or even hydrogen or air, the issuing 

 gas carries away with it large quantities of the new nickel- 

 containing vapour. After about an hour the quantity of 

 this vapour evolved becomes less, and finally its evolution 

 ceases. The property of the nickel to produce it is re- 

 stored by heating it to 400° again and allowing once more 

 to cool ; indeed, up to a certain limit it forms the com- 

 pound more abundantly after repeated use. If the issuing 

 gas is collected and heated to 150°, its volume is found to 

 largely increase, nickel more or less contaminated with 

 carbon being deposited. At a temperature of 180° the 

 nickel deposited was found to be quite free from carbon. 



The new volatile compound was eventually isolated by 

 leading the mixed issuing gases through condensers 

 placed in a freezing mixture of ice and salt, in which the 

 vapours condensed to a colourless mobile liquid of very 

 high refractive power. 



