October 20, 1892] 



NATURE 



oy/ 



obtained was mixed with water containing barium hydrate 

 partly in solution and partly in suspension, and the whole main- 

 tained for half an hour at o°, the odour of ihe brom-aldehyde 

 disappeared almost completely. Upon removal of the baryta 

 by sulphuric acid and the hydrobromic and sulphuric acids by 

 lead carbonate, the filtered liquid was found to contain glycol 

 aldehyde, which could be concentrated by evaporation over oil 

 of vitriol in vacuo. The solution of glycol aldrhyde reduces 

 Fehling's solution with great energy at the ordinary tempera- 

 ture. When warmed with a solution of phenylhydrazine in 

 acetic acid crystals of an osazone are deposited, just as hap- 

 pens in the case of other members of the series of sugars. 

 Glycol aldehyde is readily oxidized by bromine water to glycollic 

 acid, CHjOH.COOH. When treated with a dilute solution of 

 sodium hydrate polymerization occurs, a sugar of the compo- 

 sition CiUgO^, the first synthetical tetrose, being formed, 

 which is readily isolated in the form of its osazone (phenyl, 

 hydrazine compound). This osazone appears to be identical 

 with one obtained by Prof Fischer from one of the oxidation 

 products of natural erythrite. The preparation of glycol alde- 

 hyde completes the synthesis of the whole of the membeis of 

 the series of sugars, from the first member up to the sugars 

 containing nine atoms of carbon, with the exception of pentose. 

 This latter sugar Prof. Fischer hopes shortly to obtain from the 

 tetrose above described. 



The additions to the Zoological Society's Gardens during the 

 past week include a Grivet Monkey {Cenopithccusgriseo-viri- 

 dis 9 ) from Zanzibar, a Bengal Fox {Canis bengalensis) from 



Pondicherry, presented by the Rev. J. W. Scarlett ; a 



Monkey {Cercopithecus sp. inc.) from the Zambesi, presented by 

 Mr. Joseph A. Moloney ; a Bonnet Monkey {Macacus sinicus) 

 from India, a White Stork (Ciconia alba), European, presented 

 by the Rev. Sidney Vatcher ; a Mona Monkey {Cercopitkecus 

 mono) from West Africa, presented by Miss Synge ; a Hairy 

 Armadillo {Dasypusviliosua) from South America, presented by 

 Mr. J. H. Hamilton Benn ; a Common Badger {Meles taxus), 



British, presented by Mr. W. Butler; a Galago {Galago 



sp. tnc. ) ixoxn East Africa, presented by Mr. Thomas E. C. 



Remington, ; an Ichneumon ( ), a Purple-crested 



Touracou {Corythaix porphyreolophus), two Black Gallinules 

 {Lininocorax ;«>-^r),aTambourine Pigeon { Tympanistria bicolor), 

 an Emerald Dove {Chalcopelia afer), four Half-collared Doves 



{ Turtur semitorquatus), a 1- ruit Pigeon ( Treron sp. inc. ), four 



Tree ¥Tog^{Hylambat£s maculalus), ^even Smooth-clawed 



'Progs {Xenopus liBvis) iromEdiSi Africa, presented by General 

 Mathews ; three Mured Guinea Fowls [Nuinida mitrata), a 



Snake {Philothammis seniixariegatus) from East Africa, 



presented by Mr. W. Hall Buxton MacDonald, M.D. ; a 



Pratincole {Glareola sp. inc.), a Half-collared Dove {Tnrtur 

 semitorquatus), a Nilotic Crocodile {Cro.odilus niloticus) from 



East Africa, presented by Mr. R. MacAllistcr ; two 



Francolins {Francolinus ), a Coucal {Centropus ), 



five Half- collared Doves (Turtur setnito' quatus) Irom East 

 Africa, a Black-tailed Hawfinch Coccothraustes melanurus) kom 

 Japan, presented by Mr. F. Pordage ; a Flap-necked Chameleon 

 {Chamaileon dilepis), two Square-maiked Toads {Bufo regular is) 

 from East Africa, presented by Mr. E. Mdlar; a Galeated 



Pentonyx [Pelomedusa galeata), two Skinks (Gerrhosaurus 



major), five Geckos {Hetnidactylus mabouia), three 



Lizards [Mabuia striata) from East Africa, presented by Mr. 

 Frank Finn, F.Z.S. ; a Common Quail {Coturnix communis), 

 captured at sea, presented by Mr. A. Torrie ; a Honey Buzzard 

 {Buteo apivorus) from France, presented by M. S. A. Pichot 

 C.M.Z.S. ; a Burrowing Owl [Speoiyto cunicularia) from South 

 America, presented by Mr. R. B. Shipway ; two Common Boas 

 (Boa constrictor) from Trinidad, presented by Messrs. Mole and 

 Urich ; a Black-headed Lemur (Lemur brunneus) from Mada- 

 NO. 1199, VOL. 46] 



gascar, a Yellow-tailed Rat Snake (Spilotes corais) from Trinidad, 

 deposited ; an African Wild Ass (Equus tceniopus), born in the 

 Gardens. 



OUR ASTRONOMICAL COLUMN. 



A New Comet.— A telegram from Kiel announces the dis- 

 covery of a new comet by Prof. Barnard on October 12 last, at 

 lyh. 12 •2m. mean Lick time. The position, as therein stated, 

 was R.A. 293° 29', and Declination -f 12° 33'. As this new 

 comet is termed "very dim," as seen with the large Lick re- 

 fractor, it is needless to say that few instruments can at present 

 observe it. 



Our Sun's History— The question of "How our Sun 

 commenced to grow hot," is the subject of an article by Lord 

 Kelvin in the October number of L' Astronomic. In these few 

 pages he deals with various questions, among which may be 

 mentioned : What is the temperature of the Sun ? Is it increas- 

 ing or diminishing? What was the slate of the matter consti- 

 tuting our Sun before it was united into a single mass and began 

 to grow hot ? The answer to the last question leads him into the 

 method of construction of our solar system. In considering the 

 question of the encounter between two bodies as the origin, he 

 finds that the probability of such an encounter between two 

 neighbouring stars belonging to a large number of bodies, 

 attracting one another mutually, and scattered in space, is much 

 greater if they are at rest than if they are moving, even if their 

 velocities are greater than those acquired in falling from rest. 

 As an explanation of this Lord Kelvin takes the case of two 

 solid and cold bodies of diameters equal to half that of the sun, 

 and of mean densities equal to that of the earth, and supposes 

 them at rest, the mean distance between each other being that 

 of the earth from the sun. The collision caused by mutual 

 attraction will transform the bodies into a fluid, incandescent 

 mass, and he describes how this mass will arrange itself round 

 I this surface of collision. The next case he takes is similar to 

 I the one above, only the bodies have originally considerable 

 ! velocities. Further on, as a special instance, he assumes the 

 I presence of 29 millions of solid cold globes, each having a 

 j mass equal to that of our moon, and the total masses of which 

 ' are equivalent to that of our sun. These bodies, absolutely at 

 I rest, are supposed to be disseminated uniformly on the surtnce 

 ! of a sphere (radius = tfrrestrial orbit), and allowed to fall towards 

 j the centre of the sphere by attraction. The result, 10 state 

 briefly, is a mass of highly heated vapour, which afterwards 

 expands and contracts consecutively, forming a gaseous nebula, 

 I measuring forty times the radius of the terrestrial orbit. By 

 I supposing that, instead of absolute rest at the commencement, 

 these moons have a certain movement, the total sum of which 

 represents a moment of rotation round a certain axis, equal to 

 the moment of rotation of the solar system, this nebula w ould 

 be a more or less facsimile of our solar system in its earlier stage, 

 as figured out by La Place for his nebular theory. Thus this 

 theory, " founded by La Place on the history of the sidere.1l uni- 

 verse such as Herschel observed, and completed in itsdelails by 

 his profound dynamical judgment and imaginative genius, appears 

 to-day a truth demonstrated by thermodynamics." For the 

 theory of the sun, Lord Kelvin says in conclusion that the 

 antecedents immediately before incandescence cannot be 

 definitely staled, since the latter may have been caused by large 

 and few bodies, or by agglomerations of such bodies as 

 meteorites. 



Silvering Glass Mirrors. — Mr. Common, in the 

 Observatory for October, gives a brief account of various pro- 

 cesses and methods for producing good reflecting surfaces. In 

 the short historical sketch we find that the modern process is 

 due to an observation of Baron Liebig, who, in 1835, found 

 that on heating aldehyde with an ammoniacal solution of silver 

 in a glass vessel a brilliant deposit of metallic silver was de- 

 posited on the surface of the glass. In all the methods used up 

 till quite recently the surface to be silvered had to be sus- 

 pended over the baih, owing to the formation of mud which 

 settles down and prevents the proper deposition of silver ; 

 thus really large surfaces could not be dealt with. This was 

 the case with Mr. Common's 3 foot, a pneumatic arrangement 

 being made to hold the mirror by the back. In dealing with 

 the 5-foot, this method could not be so easily applied, and 

 experiments were made to find some means by which this 

 "mud" could be entirely eliminated. This was successfully 



