Dec. 7, 1 888.] 



SCIENTIFIC NEWS. 



5Si 



adjustable whilst rotating by a simple lever, and by this 

 means the white patch can be made to appear too light 

 and too dark in rapid succession. By gradually diminish- 

 ing the range of oscillation of the lever, a position of equal 

 luminosities can be found. The coloured surface is now 

 replaced by a white one, and the adjustment again made ; 

 and from the angular apertures required in the two 

 cases the relative luminosities are determined. 



Comparisons made in this way (the numbers relating 

 to which are given in the paper) with emerald-green, 

 vermilion, French ultramarine, etc., gave results in close 

 agreement with those deduced from the luminosity curves 

 obtained by the spectrum method. 



In reply to questions, Captain Abney said the spec- 

 trum method was the more accurate, and could be relied 

 on to 1 per cent. The new method gave results within 

 2 per cent., showing that the eye is very sensitive to 

 small changes of luminosity when such changes take place 

 in rapid succession. 



Professor Rticker made a communication " On the 

 Suppressed Dimensions of Physical Quantities." 



Professor Carey Foster, after discussing the effects of 

 defining specific heat as a ratio, or as a quantity of heat 

 on the dimensions of temperature, pointed out that as 

 quantity of heat = temperature x entropy, the dimen- 

 sions of temperature would be determinate if those of 

 entropy were found. 



Professor S. P. Thompson considered part of the 

 difficulties of dimensional equation arose from the fact 

 that no distinction was made between scalar and vector 

 quantities. 



ZOOLOGICAL SOCIETY OF LONDON. 

 At the meeting held on November 20th, Professor 

 Plower, C.B, LL.D., F.R.S., President, in the chair, 

 the Secretary read a report on the additions that had 

 been made to the Society's Menagerie during the months 

 ol June, July, August, September, and October, 1888, 

 and called attention to the acquisition of three specimens 

 of Pallas's Sand-Grouse (Syrrhaptes paradoxus), captured 

 out of the many flocks of this Asiatic bird that have 

 lately visited the British Islands. A letter was read 

 from Professor J. B. Steere, C.M.Z.S., giving a pre- 

 liminary account of the " Tamaron," a Bovine animal 

 found in the Island of Mindoro, Philippines, which he 

 believed to be allied to the Anoa of Celebes. Mr. Edgar 

 Thurston, C.M.Z.S., exhibited and made remarks upon a 

 collection of corals from the Gulf of Manar, Madras 

 Presidency. Mr. H. Seebohm exhibited and made 

 remarks on a specimen of a new species of pheasant 

 (I'/iasianus tarimensis), obtained by General Prejevalsky 

 at Lob Nor, Central Asia. Mr. H. Seebohm also exhibited 

 a specimen of a species of plover new to the British Islands 

 ( Vancllus grcgarius), which had been shot in Lancashire 

 about 25 years ago, and had been previously supposed 

 to be a cream-coloured courser. Mr. J. W. Hulke, 

 F.R.S., F.Z.S., read a paper on the " Skeletal Anatomy 

 of the Mesosuchian Crocodiles, based on fossil remains 

 from the clays near Peterborough, in the collection of 

 A. Leids, Esq., of Eyebury." The author remarked that 

 within the primary divisions of the order the definition 

 of species had, as Strauch had remarked twenty years 

 ago in his excellent " Synopsis of Extant Crocodiles," 

 ever been one of the more difficult tasks of the syste- 

 matic herpetologist. This he attributed largely to the 

 mutability of the characters, chiefly external, employed ; 

 but principally to the inadequacy of the osteological 



material then available for the purpose. This latter 

 want was at the present time scarcely less than when 

 Strauch wrote, yet an exact and comprehensive acquaint- 

 ance with the anatomy of the Mesosuchia must constitute 

 the only secure and enduring basis of classification. In 

 treating of extinct forms the difficulty was much 

 increased. The collection of Mr. Leids contained a large 

 series of crocodilian remains from the Oxford Clay in 

 admirable preservation, which illustrated many anato- 

 mical details not to be learned from the skeletons 

 embedded in slabs of rock contained in public museums. 

 The author described a selection of bones from Mr. 

 Leids's collection illustrative of the two chief families 

 into which Messrs. Deslongchamps (pere et fils) had 

 divided the Teleosauria. The skeletal differences of the 

 Teleosauria proper, and Metriorhynchi, and those exist- 

 ing between both these and the Eusuchian skeleton were 

 pointed out ; and the morphology of certain bones was 

 discussed. Mr. Oldfield Thomas, F.Z.S., read a paper 

 on a " Collection of Small Mammals obtained by Mr. 

 William Taylor in Duval County, South Texas." The 

 collection contained examples of one new species and 

 one new geographical variety, besides adding no less 

 than six species to the National Collection of Mammalia. 

 A communication was read from M. L. Taczanowski, 

 C.M.Z.S., containing a "supplementary list of the birds 

 collected in Corea by Mr. Jean Kalinowski." 



EDINBURGH ROYAL PHYSICAL SOCIETY. 

 At the meeting on November 21st, Dr. Sims Wood- 

 head, F.R.S.E., Vice-President, in the chair, the 

 Secretary, Dr. Traquair, F.R.S., submitted a paper 

 " On the Structure of Ptericlitliys and its Allies," 

 comparing it with the genera of Asterolepis and 

 Borthriolepis. After remarking that some geologists have 

 denied that Plcrichthys was a fish, he went on by the aid 

 of numerous specimens and casts to describe the more 

 salient structural arrangement. Regarding the curious 

 shield on the top of the head, he was inclined to believe 

 it to have been a guard for the eyes, which, by an ar- 

 rangement of muscles, could be raised or lowered at 

 will. In a second paper "On Homosteus, Asmuss(Hugh 

 Miller's Asterolepis of Sromness)," Dr. Traquair agreed 

 with the Continental authorities that it must be classed 

 as a Piericlithyan fish, and exhibited a beautiful cast of 

 an exceedingly fine specimen. Mr. Harvie-Brown sub- 

 mitted a paper " On the Seal in Fresh Water," in which 

 the occurrence of the seal in Loch Awe, first noticed in the 

 Old Statistical Account, 1793, was traced down to the 

 present time. It had been supposed at one time that 

 the seal had made its way up the rapid river Awe in 

 pursuit of salmon, but the opinion now held pointed to 

 their presence in the loch as being due to physical 

 changes. In the course of a discussion which followed, 

 it was pointed out that Dr. John Murray's recent dis- 

 covery of organisms in the locks of the west coast, which 

 are not found anywhere else within the 100-fathom line, 

 went far to support the theory of geological changes im- 

 prisoning animals in what might be considered quite 

 unsuitable localities, but to which they had adapted 

 themselves. In this way it was quite possible that the 

 seals of Loch Awe had lived there from generation to 

 generation. The physical features of the surrounding 

 district were also remarked upon as showing evidence of 

 late geological changes. Mr. George Brook, F.L.S., read 

 a short note on a " roller " lately shot in Mull by Mr. 



