July 14, 1881] 



NATURE 



239 



affords a true sequence of ideas that have taken place in the 

 minds of the savages who made these things. And it is in 

 complete analogy with the development of ornamentation in 

 other places, of which several examples are in my museum. 

 The interest which attaches to tuch specimens of savage art and 

 ornament is purely psychological. Taken as the representatives 

 of ideas, and arranged to show the development of ideas, they 

 serve important purposes in the study of social evolution, ex- 



of ordinary ice becoming hot, Dr. Pettersson describes Dr. Car- 

 nelley's ice as condensed and not frozen. In those experiments 

 of Dr. Ciinelley's ^^hich I have seen, the water was frozen 

 round the thermometer, and not condeuFcd on it. The matter 

 therefore ;eems to stand thus :— If the ice does really become 

 hot, the limit of the ice-surface is most probably along m k, 

 whereas if Mr. Hannay and others are correct in stating that the 

 temperatures of the ice and condenser are identical, the limit 

 must be along m q, and not along m I, which latter 

 is the line denoting the maximum tension of the 

 vapour of water cooled below the freezing point 

 without solidifying, and not of ice below the freez- 

 ing point. 



I would just say also that the idea of an allotropic 

 modification of ice did not occur to me. 



..Sydney Young 

 The Owens College, Manchester 



plaining by analogy the law which has operated in producing 

 many otherwise unaccountable conditions of custom, religion, or 

 institution?, of which the successive phases of thought, having 

 never been embodied in t.angible forms or committed to writing, 

 cannot be reproduced or arranged in their true order of succes- 

 sion. The sequence therefore is often lost, and wrong causes 

 are assigned to them. A. Pitt Rivers 



Hot Ice 



Having read a paper before the Owens College Chemical 

 Society on January 21, in explanation of Dr. Carnelley's experi- 

 ments, in which I treated the subject in a similar way to Dr. 

 Pettersson, perhaps I may be allowed to point out one or two 

 differences in my explanation from that given by Dr. Pettersson 

 in Nature, vol. xxiv. p. 176. 



In the first place Dr. Peitersson speaks several times of the 

 point m (the triple point) as being o°'oo7S C. below zero, whereas 

 it must be above, because the melting-point of ice rises as the 

 pressure is diminished. 



After describing the line mk, which I believed then to exist, 

 and which will probably be found really to exist if ice can be 



heated. Dr. Pettersson says that in the case of ordinary ice it 

 has been proved that ice does not get hot, and that the limit of 

 the ice-surface is along / in, a continuation of the water-steam 

 line III fi. 



Now Prof. James Thomson describes m as the point of inter- 

 section of three different lines, n m, dm, and q m, the water-steam, 

 water-ice, and ice-steam lines ; m q being, not a continuation of 

 n III, but a separate line, the difference in position being due of 

 cour.-e to the latent heat. 



I fail to see also how in k can be considered a continuation of 

 dm, any than more of n,m. Lastly, after denying the possibility 



Note on Piczorhynchus melanocephalus 

 (Ramsay), and Ptilopus viridis (Ramsay), 

 from the Solomon Islands 

 Having lately received several specimens of 

 the Piczorhynchus, which I described under the 

 above name, I find that it is the young of Mr. 

 Tristram's P. vidua (see Proc. Linn. Soc. of New 

 South Wales, vol. iv. p. 46S) from the Solomon Islands. The 

 white collar which commences on the nape is much broader in 

 the young than in the adult, and the feathers of the chest are 

 while, all margined consjiicuously with black. 



Specimens have been obtained on the island of " Ugi," one of 

 the Solomon group. 



I believe the fruit pigeon I determined a.s Ptilopus viridis, 

 from the Solomon Islands, will prove to be the female of Ptilopus 

 argenia. Gray, of which I have recently seen some fine speci- 

 mens collected bv the Rev. George Brown and Lieut. Richards, 

 R.N., at "Ugi." Ed. P. Ramsay 



Anatomical Museum, Sydney, April 



THE BRITISH MUSEUM CATALOGUE OF 

 BIRDS ^ 



AS has been more than once remarked in our pages, it 

 would require more than one man's lifetime to com- 

 plete the Catalogue of Birds, if the rate at which the first 

 four volumes were produced had to be continued. Mr. 

 Bowdler Sharpe, who has written these first four volumes, 

 was a young man when he commenced his task, but at 

 the same rate of progress it would have reciuired him to live 

 nearly a hundred years to finish the Catalogue by himself. 

 Dr. C'.iinther has therefore had to seek assistance froin out- 

 side the walls of the Museum, and has engaged the services 

 of Mr. Seebohm to bring out the fifth volume of the Cata- 

 logue, which contains a description of the family Tuniida, 

 containing the Thrushes and Warblers. As Mr. Seebohm 

 has devoted several years to a study of this family, he 

 possesses a special knowledge of his subject probably 

 unequalled by any other ornithologist. It must be re- 

 membered that, as in the case of Dr. Gunther's Catalogue 

 of Fishes, the Catalogue of Birds is not a mere list of 

 specimens in the national collection, but is in reality a 

 monographic n'suiiu' of the birds of the world. If we 

 look through the first four volumes of this laborious work 

 vi^e shall find that not only are the species in the British 

 Museum thoroughly described, but that species not included 

 in the collection of that institution are also treated of, and 

 the types of raie birds in Continental museums are fully 

 described : showing that Mr. Sharpe was not content to 

 work solely with the collection under his charge, but that 

 he has compared his notes with the specimens in many 

 of the museums of Europe, and has therefore done his 

 utmost to make the Catalogue in every way complete. 

 But if this is true of the first volumes, it is ten times 

 more so in the case of the fifth, which now lies before 

 us. C)n turning over its pages we see that Mr. Seebohm 

 has not only visited European museums, but has even 



' Vol. V.,. Containing the Family Tnrdida, by Henry Seebohm. 



