Nov. 25, 1886] 



NATURE 



Let Q o P be this limiting angle. Take R on O P, and draw 

 R s to n at CO along o Q. 



Then if s is at co , the perpendicular s p falls at an infinite 

 distance from R. 



. •. Angle p R s not greater than p o Q, and it cannot be less 

 (Eucl., I., 16 and 27). 



Hence it must be equal. 



Hence R s making the angle s R P = Q o p meets o Q at 00 at 

 both ends. 



Anil any other straight line through R becoming infinitely 

 distant from R s must cut o Q in some finite point. 



Thus from K only one parallel, R s, can be drawn to a given 

 line, OQ. 



By moving o P along o Q always at the same angle, Q o p, we 

 can show that 



From a given point only one parallel can be drawn to a given 

 line. 



This theorem, therefore, must be true. E. Budden 



SCIENTIFIC SERIALS 



America)! yoiirnal of Science, October. — A dissected vol- 

 canic mountain ; some of its revelations, by James D. Dana. 

 Here the .author returns to the subject of Tahiti, largest of the 

 Society Islands, already described by him in 1850 from mate- 

 rials supplied by the Wilkes Exploring Expedition of 1839. 

 The old cone, some 7000 feet high, is now a dissected moun- 

 tain, with valleys cut profoundly into its sides, and laying bare 

 the centre to a depth of from 2000 to nearly 4000 feet below the 

 existing summit. As shown on the accompanying map, the 

 valleys, due to erosion, are so crowded on one another, that the 

 dissection is complete, thus disclosing the inner structure of a 

 great volcanic mountain. The interior is shown to be com- 

 posed, not of lava-beds, there being no horizontal lines, but of 

 imperfect columnar formations, rising vertically in the unstrati- 

 fied mass quite to the summit. The uniform massiveness 

 through so great a height at the volcano's centre is attributed to 

 the cooling of continuously liquid lava in the region of the great 

 central conduit of the cone. A comparative study of Mauna 

 Loa (Hawaii), shows that such a massive central structure is a 

 common feature of the greater volcanic mountains, the extremely 

 slow cooling process under great pressure causing the lava to 

 solidify into a compact crystalline rock, and often into a coarsely 

 crystalline rock. — Origin of the ferruginous schists and iron ores 

 of the Lake Superior region, by R. D. Irving. Rejecting the 

 igneous theory, now held by few, the writer, after a careful 

 survey of the whole field, concludes that these rocks were 

 once carbonates analogous to those of the coal-measures, which 

 by a process of silicification were transformed into the various 

 kinds of ferruginous formations now occurring in this region. — 

 Further notes on the artificial lead silicate from Bonne Terre, 

 Montana, by H. A. Wheeler. An analysis of this interesting 

 substance, which was found under the hearth of an old reverbera- 

 tory roasting- furnace, yielded 73 '66 PbO, 17' 1 1 SiOo, NiO 3 '06 

 (coarse crystals), 72*93 PbO, iS'5i SiOo, and smaller quantities 

 of nickel, cobalt, and other ingredients. — Limonite pseudo- 

 morphs after pyrite, by John G. Meem. The paper gives a 

 short account of the pseudomorphs occurring in Rockbridge 

 County, Virginia, where they are associated with Lower Silurian 

 limestones. These crystals, v.arying in colour from a very light 

 to a very dark brown, and sometimes almost black, are hydrous, 

 and yield a yellow powder, showing them to be limonite, most 

 commonly of octahedral form. — Note on the hydro-electric 

 efifect of temper in case of steel, by C. Barus and V. Strouhal. 

 The object of this inquiry is to determine directly the carbon 

 relations of steel as a function of the temperature (0° to 400°, 

 400' to 1000°) and of the time of annealing, with full reference 

 to the physical occurrences observed in the first and second 

 phases of the phenomenon. — On the crj'stalline structure of iron 

 meteorites, by Oliver Whipple Huntington. It is shown that 

 the usual classification of these meteorites into octahedral and 

 cubic crystals cannot be natural or fundamental. A careful ex- 

 amination of the large collection belonging to Harvard College, 

 containing types of all the characteristic meteorites of this class, 

 leads to the conclusion that masses of meteoric iron are cleavage 

 crystals, broken ofi' probably by impact with the air, and show- 

 ing cleav.ages parallel to the planes of all three fundamental forms 

 of the regular system (octahedron, cube, and dodecahedron) ; 

 further, that the Widmanstattian figures and Neumann lines 



themselves are sections of planes parallel to these same forms, 

 exhibited in every gradation from the broadest bands to the 

 finest markings, with no natural break, the features of von 

 Widmanstiitten's figures being, moreover, due to the elimina- 

 tions of impurities during the process of crystallisation. — A new 

 meteoric iron from Texas, by W. Earl Hidden. The specimen 

 here described and illustrated was discovered by Mr. C. C. 

 Cusick on June 10, 1SS2, near Fort Duncan, Maverick County, 

 Texas. It weighs over 97 pounds, is quite soft, being easily cut 

 with a knife, and consists of iron 94'90 ; nickel and cobalt, 4'87 ; 

 phosphorus, 0'25, with traces of sulphur and carbon ; specific 

 gravity, 7'522. — On pseudomorphs of garnet from Lake Superior 

 and Salida, Colorado, by S. L. Penfield and F. L. Sperry. The 

 Lake Superior specimen is essentially an iron alumina garnet, 

 with formula Fe.jAUSijOjo. That of Colorado is higher in 

 protoxides and water, the increase being perhaps due to the pre- 

 sence of ripidolite. — Further notes on the meteoric iron from 

 Glorieta Mount, New Mexico, by George F. Kunz. — On the 

 Brookite from Magnet Cove, Arkans.as, by Edward S. Dana. 

 These crystals, first described in 1846 by Shepard under the 

 name of arhatisite, are especially remarkable for the great 

 variety of their forms, which is most unusual for crystals 

 occurring in the same locality. 



SOCIETIES AND ACADEMIES 



London 

 Zoological Society, November 16. — Prof. W. H. Flower, 

 F. R. S., President, in the chair. — An extract was read from a 

 letter addressed to the President by Dr. Emin Bey, dated 

 Wadilai, Eastern Equatorial Africa, Janu.ary i, 1886, and con- 

 taining some notes on the distribution of the Anthropoid Apes 

 in Eastern Africa. — A letter was read, addressed to the Secre- 

 tary by Dr. Chr. Liitken, of Copenhagen, F.M.Z.S., containing 

 some information as to the locality of Chiropodomys penicillatus. 

 — A letter was read from Dr. A. B. Meyer, C.M.Z.S., com- 

 municating some remarks by Mr. K. G. Henke on a specimen 

 of a hybrid Grouse in the Dresden Museum. — Prof. Flower, 

 F. R. S., exhibited and made remarks on a specimen of a rare 

 Armadillo {Talusia pilosa) belonging to the Scarborough Mu- 

 seum. — Prof. Bell exhibited, and made remarks on, an object 

 (apparently of the nature of an amulet) made from a portion of 

 the skin of some mammal, and received from Moreton Bay, 

 Australia. — Mr. H. Seebohm, F.Z. S., exhibited a skinof what he 

 considered to be a young individual of the Lesser White-fronted 

 Goose {Anser albifrons minutus), shot in September last on Holy 

 Island, oft' the coast of Northumberland, and observed that it 

 was the first recorded example of the small form of the White- 

 fronted Goose which had been obtained on the coasts of our 

 islands. — Mr. Blanford, F.R.S., exhibited, and made remarks 

 on, a mounted specimen of a scarce Paradoxure (Paradoxiinis 

 jerdoni) from the Neilgherry Hills in Southern India. — A com- 

 munication was read from Colonel Charles Swinhoe, F.Z. S., 

 containing an account of the species of Lepidopterous insects 

 which he had obtained at Mhow, in Central India.— A commu- 

 nication was read from Dr. R. W. Shufeldt, C.M.Z.S., contain- 

 ing an account of the anatomy of Geococcyx californianus. — 

 Mr. Lydekker described three crania and other remains of 

 SceliJolherium, two of the former being from the Argentine 

 Republic, and the third from Tarapaca, in Chili. One of the 

 crania from the first locality he referred to the typical S. lepto- 

 ccphaltim of Owen, while the second, which had been described 

 by Sir R. Owen under the same name, he regarded as distinct, 

 and proposed to call i'. bravardi. The Tarapaca form, which 

 was characterised by the extremely short nasals, was also re- 

 garded as indicating a new species, for which the name of 5. 

 ehiUnse was proposed. The author concluded that there were 

 not sufficient grounds for separating Lund's proposed genus 

 Platyonyx from Scelidot/wrium.—'Mi. G. A. Boulenger pointed 

 out that two distinct forms of the Batrachian genus Boinbinalor 

 occur in Central Europe, and read notes on their distinctive 

 characters and geographical distribution. — A communication 

 was read from Dr. R. W. Shufeldt, containing a correction, 

 with additional notes, upon the anatomy of the Trochili, 

 Capri miilgi, and Cypselida:. — A communication was read from 

 Dr. R. A. Philippi, C.M.Z.S., containing a preliminary notice 

 of some of the Tortoises and Fishes of the coast of Chili. — Mr. 

 Sclater exhibited the head of, and made remarks upon, an 

 apparently undescribed species of Gazelle from Somali Land. 



