yuly 9, 1874] 



NATURE 



191 



ductor. Some of the powdered substances appear to 

 require a small spark to be passed through them before 

 they allow a larger charge to pass, as if the particles 

 needed polarisation. 



G. H. Hopkins 



THE HERPETOLOGY OF NEW GUINEA* 



DR. ADOLF BERNHARD MEYER, who, as most 

 of the readers of Nature will be aware, has 

 lately returned from a very successful expedition to New 

 Guinea, has published in the " Monatsberichte" of the 

 Berhn Academy a short account of his herpetological dis- 

 coveries, which present several points of interest. Pre- 

 vious investigators of the natural history of this wonderful 

 land have paid more attention to its birds than to its 

 reptiles and amphibians- a circumstance perhaps scarcely 

 to be wondered at in the land of paradise-birds and so 

 many other anomalous forms. Dr. Meyer, however, while 

 he has by no means neglected the class of birds, as shown 

 by his recent communications upon that branch of zoology 

 to the Academy of Vienna, has likewise paid much atten- 

 tion to the representatives of the inferior orders of rep- 

 tiles and balrachians which he met with in New Guinea 

 and the adjacent islands. Although this branch of the 

 Papuan fauna is well known to be comparatively poor, 

 Dr. Meyer's labours have been by no means without result. 

 Of sixty-three different forms belonging to these orders 

 of which he collected specimens, thirty-four have turned 

 out to be new to science ; and of the remaining twenty- 

 nine, the greater part were previously not known to occur 

 in this locality. 



Of tortoises, besides the marine Clidoiic iinbricata, 

 only one was obtained in New Guinea, which, however, 

 was of a new species belonging to an Australian form. 

 Of lizards, upwards of thirty species were collected, 

 amongst which Australian types are again predominant. 

 Amongst the sixteen serpents met with in New Guinea, 

 Jobi, and !\Iysore, were several of special interest. The 

 Australian carpet snake, MoicUa, is represented by an 

 allied form, proposed to Idc called Chondropyllioii, besides 

 which two other new gencia are described, one belonging 

 to the boas, and the other to the colubrine snakes. 



Of batrachians, Dr. Meyer collected specimens of nine 

 species in New Guinea and its islands, five of which he 

 considers to be hitherto undescribed. 



It will be thus evident that Dr. Meyer has made a by 

 no means inconsiderable addition to our knowledge of 

 this br.anch of the Papuan fauna. At the same time it 

 cannot, be supposed that we are, as yet, by any means 

 perfectly acquainted with the hcrpctology of New Guinea 

 when so little is known of the vast interior of this strange 

 country. 



COGGLVS COMET 



A N observation taken here on July 4, shows so 

 -^*- close an agreement with the position calcu- 

 lated from my parabolic elements in Nature (vol. 

 X. p. 149), tli.at it appears unlikely the comet can 

 have so short a period as 137 years, and consequently 

 that, notwithstanding similarity of orbits, it probably is 

 not identical with the body observed by the French 

 Jesuits in China in July 1737. Between April 17, the 

 date of discovery, and j>>lv 4 it had traversed an arc of 

 just 90' of true anomaly, xnd if any decided ellipticity 

 existed, so wide an arc must have shown it, the stellar 

 appearance of the nucleus having admitted of very exact 



* " Uebersiclit der von mir auf Neu Guinea, undden Inseln Jobi, Mysore, 

 und Mafoer im Jahre 1873, gesaramelten Ampliibien." Von Dr. Adolf Bern- 

 hard Meyer. (Berlin : MonaUb. Akad., 1874.) 



observation throughout. On July 4, twenty-one days after 

 the last position 1 employed in determining the orbit, the 

 computed right ascension differs only 20", and the decli- 

 nation 14" from the observation. In all probability, 

 therefore, the comet has not visited these parts of space 

 within many centuries. 



Measures of the diameter of the nucleus on July 4 gave 

 nearly 14 seconds of arc, the distance of the comet at the 

 time, by my elements, being o'6oi6, which indicates a 

 real diameter of about 3,750 miles ; it has, perhaps, 

 slightly contracted within the last fortnight. 



This morning Mr. W. Plummer, at this observatory, 

 found the comet equal in brightness to a Persei, a second 

 magnitude star in Argelander's Atlas. 



I may here mention that for calculation of actual di- 

 mensions or distances I take the sun's parallax-, after M. 

 Leverrier = 8"'S6, which, combined with Capt. A. E. 

 Clarke's value of the earth's equatorial semi-diameter, gives 

 for the mean distance of the earth from the sun, 92,268,000 

 miler, a figure that I believe to be as probable as any now 

 to be attained. The moon's mean distance from the 

 earth, adopting Prof. J. C.Adams's parallax, is thus found 

 to be 238,800 miles, or 60273 equatorial radii of our 

 globe. J. R. Hind 



Mr. Bishop's Observatory, 

 Twickenham, July 7 



DE CANDOLLE'S PROPOSED "PHYSIO- 

 LOGICAL GROUPS" OF PLANTS 



T N the Archives dt's Sciences Physiques et Na/itrelles, 

 •*■ No. 197, M. de Candolle proposes a new classification 

 of the vegetable kingdom, based on the physiological re- 

 lations of plants to heat and moisture, which he believes 

 afibrds a means of tracing the connections of recent and 

 fossil floras in a way which neither botanical nor 

 geographicak grouping do. He makes six divisions 

 altogether. 



T. The first of his " physiological groups " consists of 

 those which need much heat and much moisture, and to 

 them he gives the name Hydromegatherm, or, for short, 

 Megatherm. These at present live in the tropics, 

 and sometimes as far as 30" N. and S., in warm and damp 

 valleys, where the temperature is never below 20'' C, and 

 the rains never fail. The predecessors of the existing 

 Megathcrms were widely spread, but at the commence- 

 ment of the Tertiary period they became confined pretty 

 much to the equatorial zone. Their botanical characters 

 vary considerably, and they are represented in almost all 

 cases by different species in Asia, Africa, and America. 

 The most characteristic families are Menispermaceae, 

 Byttneriaceas, Ternstrcemiacere, Guttifcric, Sapindaceae, 

 Dipterocarpea:, Sapotacea;, Apocinacea;, Aristolochacas, 

 Begoniace;c, Piperacea", &c. 



2. His second group requires heat with dryness — Xero- 

 philes he proposes to call them. Their present distribu- 

 tion is in dry and warm regions of from 20" or 25° to 30" 

 or 35° on each side of the equator (their particular 

 districts are carefully noted). The group includes a large 

 proportion of Composit;i;', I.abiata?, IJoraginacea^ Liliaceas, 

 Palm.'c, MyitacccC, Asclepiadacex-, Phiphorbiacea} ; but the 

 most characteristic are Cactaccx', Ficoide;o, Cycadacea;, 

 I'rotcacecc, and Zygophj Ilea;. There are {&\v large 

 trees, few annuals, and the aspeot of vegetation is but 

 meagre. The palaeontology of the regions where Xero- 

 philes now exist is too little known for us to be able 

 to trace the former migrations of plants forming this 

 group. 



3. The third group includes those plants which require 

 a moderate heat, 1 5" to 20" C, and moderate moisture, 

 and are named Mesotherms. They arc now found around 

 the Mediterranean, in the slightly elevated regions of 

 India, of China, Japan, California, Ccniral United States, 



