Dec. 9, iS8o] 



NylTURli 



125 



express words as well as the general bent of his argument seemed 

 to point in the opposite direction. Thus at p. 81 he writes : — 

 " Language is a product of association. . . . Language is a 

 product of an active, not of a passive, jirocess ; it is the child of 

 will, not of sf.nsalion." The statement that language is "the 

 child of will " seems to me praelically identical with tlie assertion 

 that "speech is the dcliberale product of a conscious wjj'i." 

 because the will here spoken of, being "an active process," is 

 necessarily coascious. — A. H. Keane.] 



Notes on the Mode of Flight of, the Albatross 



Wlir.N watching the albatross one is struclt willi the fact 

 that the bird gets up to windward without a)>pearing to use bis 

 wings to a degree sufhcicnt to account for the same. 'I'he sailors 

 are satisfied with the explanation tliat he beats to windward. 

 The conditions are of course not analogous to tho-ic of a ship 

 sailing to windward. If the wind be very light, or if there be a 

 calm, occasional powerful and obvious flapjjing of the wings 

 occurs. If there is no wind, the birds often settle on the water 

 round the sliip. In very heavy weather the birds disappear 

 altogether, probably .settling on the water. Kxccpt that for 

 breeding they report to the islands, I believe they frequent the 

 open ocean, where the surface is seldom without more or 

 less swell. 



On watching the flight of the albatross, one observes that in 

 order to rise from the water violent and obvious (lapping of 

 the wing^ is necessary, which is continued some time after the 

 wings cea'c to strike the water. After a start has thus been 

 effected, if there is a fresh breeze, the wing-i arc kept almost 

 motionless. Sometimes the bird goes some dist.ince with the 

 impetus derived from the (lapping of the wings at the start, but 

 sooner or later he turns sm as to expose the ]jlanc surface 

 of his wings full to the force of the wind, rising at the same 

 time some height above the water, and drifts off to leeward, thus 

 soonac'iuiring the velocity of the wind ; then swooping down into 

 the hollow between two swells, he turns his head to windward, 

 ai»d keeping cloye to the surface of the water, sails along more 

 or lesi against the wind for a surprising distance ; finally, rising 

 over the crest of a wave comparatively high into the air, and 

 turning with his win^s as before, so as to catch the wind to the 

 fullest extent, he agam lets himself drift off to leeward. 



Thus the mano;uvre he performs seems to consist in drifting 

 with the wind in such a way as to attain its velocity very soon, 

 and then turning round so as to make use of this velocity to 

 carry him in the contrary direction. 



Of course if he still remained exposed to the wind which had 

 imparted to him its velocity he would not travel far against it 

 before he came to a standstill, and he would certainly make no 

 progress to windward ; but by keeping close to the surface of 

 the water, and as much as possible in the hollows Ijctwcen the 

 waves, h« is almost out of the wind ; and in this comparatively 

 calm region the impetus derived from the wind will carry him a 

 long distance in exactly the opposite direction to that of the 

 wind itself. 



This manoeuvre appears to be an important factor. No 

 ddubt the almost imperceptible movement of the wings may 

 assist, though that this alone is insofficic-nt to account for the 

 progress to windward appears evident from the powerful efforts 

 made with the wings in rising from the water and in calm 

 weather. I have never had an opportunity to observe the 

 albatross flying over land or over level water. If the manoeuvre 

 above described be an important factor, the birds then would 

 have to use their wings much as they do in very light w inds on 

 the ocean. If very strong winds were blowing, they would have 

 to settle on the land or in the water in order to remain at the 

 locality. Aktiiuk W. Bate.man 



A General Theorem in Kinematics 

 I'ROF. Kvici'.ETi' (a«/<f, p. 99) has overlooked in the inlrc- 

 ductory paragraphs of I'rof. iSciiell's paper, to which he refcis 

 for the original statement of the theorem re-discovered by Prof. 

 Minchin, the acknowledgment : "Der Mittelpunkt der Jjc^cbleu- 

 nigungcn und jene beidcn Kreise wnrden V;crcits 1853 von Bkesse 

 gefundcn.'' The reference is to the Journal <le I' f.cole Poly- 

 techniqut, torn, xx., " Mcmoire sur un 'iheoreme nouveau con- 

 cernant les Mouvements Plans, etc." By means of the ' t«o 

 circlci" Brcise determines the point c {/) "qui aura nne acetic- 

 ration totalc nolle" (p. 82), and then by very ingenious applica- 



tion of kinematic principles deduces those relations to it which 

 any arbitrary point (/") has, as given by I'rof. Minchin. Bressc 

 names c " second centre instantan<; de rotation." 



University Kail, December 4 ]. J. Walker 



Geometrical Optics 

 VouK correspondent " P. C." (Nature, vol. xxii. p. O07) 

 asks information concerning a work, in English or French, on 

 geometrical optics, thoroughly explaining the optical construction 

 of telescopes and microscopes. I am not aware of any such 

 publication these last forty years, but deem it possible that it 

 may interest your correspondent to know of the existence of such 

 a work in German by von Littrow, entitled " Uioptrik, oder 

 Anieitung zur Verfcrligung der Fernrohre." It was published, 

 I believe, in Vienna about 1838. W. G. Loceman 



High Jiurghal .School, Haarlem, Holland, November 17 

 [Littrow's " iJioptrik " was published at Vienna in 1830 in 

 Svo.— i;i).l 



Ozone 



Ik a .slip of the prepared paper, used for testing for atmospheric 

 ozone, be carefully moistened on one side with alcohol, using a 

 clean camclhair brush, on burning off the spirit and immersing 

 the slip of paijcr in water the paper changes to a deep purple 

 colour, as deep as No. 8 in Negrctti and Zambra's scale of 

 colours for ozone. 



Is this due to the development of ozone? as, according to 

 Schonbcin, heat destroys ozone. J. V. 



Leicester, December 5 



PLANTS OF MADAGASCAR 



DURI.NG the present year no less than four separate 

 collections of plants have been received at Kew 

 from Madagascar, including in the aggregate about a 

 thousand species, represented by specimens complete 

 enough to be botanically determinable. As the hills of 

 the interior of the island attain an elevation of ro,oco 

 feet, its range of climate is considerable. We now know 

 not less than tivo thousand Madagascar (lowering-plant-, 

 and probably have almost exhausted its ferns, to which 

 the collectors have paid special attention, and which are 

 about 250 in number, so that we may consider ourselves 

 in a position to draw broad general conclusions as to the 

 botany of the island. 



Amongst the tropical types there are a considerable 

 number of endemic genera. The lemurs find their 

 parallel in the vegetable kingdom in the Chlcenacea, a 

 natural order whose nearest affinities arc with Tiliacca, 

 Diptcroc<irfica:, and Tcriistromiaccce, which is strictly con- 

 fined to Madagascar, and comprises four genera and 

 about twice as many species, to which the Rev. K. I3aron, 

 in these new collections, has added a well-marked novelty 

 in a second species of Leplolcma. Altogether there are 

 certainly not less than fifty genera confined to the 

 island, some of them very curious types, as Dicoryphia 

 in Hauuunclidcce, Onvirandra in Naiar/accce, Asteropeia 

 (placed in the "Genera I'iantarum" in .Samydacea, but 

 which Mr. ]5aron's excellent new specimens will most likely 

 have to be removed to Liiiacece), Macarisia in Rhi::op)horca, 

 Deidaiiiia and Physoia in Passi/lorea;, Ilydrolriclie in 

 Scrophiilariacece, Caitctia, Tdnnodia and .Spharoslylis 

 in Kiiphorhiitcca:, Pacluiotrophc in Morea; Calantica in 

 Saiiiydiiccu!, and several each in the orders Htibiacea, 

 Mcltiil/iiimcca; and Coinposita. To these endemic types 

 the new collections add at last three, KiUluii^ia, a fine 

 new genus of Crasstilacea: allied to JSryopihyllum, with 

 five or six specie? named after the collector of the first 

 of the four parcels, Rhodocndoii, a monotypic genus of 

 gamophyllous Liliacecs allied to llyacinthus, and Micrc- 

 7tychia, in Anacardiacea:, also monotypic, figured lately 

 in Hooker's Icones. IJesides these the tropical flora of 

 the island contains a large proportion ; first, of endcrnic 

 species of genera known elsewhere ; second, of species 



