March 14, 1895J 



NA TURE 



471 



clay sinks furl her west towards Wiltshire. The lowest zone of 

 the Gault in Surrey that has the typical clayey facies is equiva- 

 lent to the fourth or higher zone of the Folkestone Gault, the 

 lower zones being represented in the so-called " Folkestone 

 Sands." Dr. Gregory indicates the levels at which, in Kent and 

 Surrey respectively, the limits of the Albian, Upper and Lower 

 .■\ptian, and Rhodanian formations of the Continent can be 

 drawn ; but insists on the necessity of continuing to recognise 

 the old lilhological divisions side by side with the new palreonto- 

 logical ones. He also gives a critically revised and extended 

 list of fossils from the phosphate beds of Great Chart, near 

 Ashford, Kent. 



The 1894 "Report of Observations of Injurious Insects 

 and common Farm Pests," by Eleanor A. Ormerod, 

 will not yield to any of its predecessors in interest, value, 

 or variety. The general character of these Reports is so 

 well known that it is unnecessary to dwell upon it ; 

 but the present part gives prominence to several con^i lera- 

 tions which have not hitherto received very much attention. 

 The first of these is the undoubted fact that almost any of the 

 12,000 species of insects inhabiting the British Islands, except 

 those which feed exclusively on other insects, may, under certain 

 circumstances, or when unusually abundant, become entitled to 

 a place in the category of injurious insects. Thus, the present 

 Report opens with figures and descriptions of three species of 

 /.ifidoflera—\he Eyed Hawk Moth, the Lappet Moth, and 

 the large Tortoiseshell Butterfly^which are not generally so 

 common in England as to be thought capable of causing serious 

 injury ; indeed. Miss Ormerod herself suggests that such pests 

 might easily be got rid of by inviting an entomologist to clear 

 I them off. One of the most important insect visitations during 

 I the past year was that of the Antler Moth (Ckamas graminis) 

 I in South Scotland, where the larvjE fed on the tender grass 

 j which sprang up over the districts previously devastated by the 

 vole plague. Several pages are devoted to hay mites, which 

 appear, however, though sometimes excessively abundant, to 

 cause little real damage. Other interesting creatures noticed 

 are the eel-worms (in her account of which Miss Ormerod has 

 unintentionally in part anticipated Prof. Percival's important 

 paper on the subject in Natural Siience for March, as fully 

 explained in an accompanying note), horse-warble, winter 

 gnats, wasps, &c. It does not appear to be quite certain 

 whether the horse-warble is the same species as the ox-waible. 

 Warble in the horse appears to be of much less common 

 occurrence than in the ox, and usually to occur only in small 

 numbers in the same animal. But this may be due to the horse 

 being a more carefully-tended animal than the ox. Two other 

 points of interest deserve notice. Several species of car- 

 nivorous ground-beetles are stated to be very destructive to 

 strawberries. More information is certainly required as to how 

 far so-called carnivorous insects will also eat vegetable matter, 

 decaying or otherwise. It appears that sea-gulls are some- 

 times in the habit of frequenting turnip- fields infested with the 

 Diamond Back Moth, and in one instance a farmer attributed 

 the destruction of his crop to the gulls. So easy is it to make 

 a serious error in discriminating between the farmer's friends 

 and foes. 



A NEW and particularly convenient method of preparing the 

 unsaturated hydrocarbon allylene, CjH^, has been discovered 

 by Prof. Keiser and Miss M. B. Breed, as the result of an 

 investigation concerning the action of magnesium upon the 

 I vapours of the alcohols. Preliminary experiments showed that 

 when magnesium is heated with organic compounds such as 

 alcohols, acids, and ketones, a reaction of considerable energy 

 occurs at more or less elevated temperatures, accompanied by 

 incandescence ol the metal. The reactions between magnesium 

 NO. 1324, VOL. 51] 



and the alcohols were then systematically studied. The mag- 

 nesium, in the form of filings, was placed in a porcelain boat, 

 and heated in a combustion tube through which the vapour of 

 the alcohol was conducted. At a low red-heat the magnesium 

 usually commenced to glow at one end of the boat, and the 

 incandescence was then rapidly communicated to the whole 

 quantity of metal, while large volumes of gas were evolved from 

 ihe tube. When methyl alcohol is employed the action is 

 extremely energetic, and the gases evolved consist mainly of 

 about four-fifths hydrogen and one-fifth marsh gas. The residue 

 in the boat is then allowed to cool in the vipour of the alcohol, 

 when it is found to have the appearance of a black coherent 

 mass. When this solid residue is placed in water a gas is slowly 

 evolved, and if a fe* drops of ammonium chloride are added, 

 the gas i-. liberated in a steady and moderately rapid current. 

 The odour of the gas resembles that of acetylene, but when it 

 is conducted through an ammoniacal solution of cuprous 

 chloride the greenish yellow precipitate of cuprous allylide is 

 produced, and with an ammoniacal silver nitrate solution the 

 while crystalline precipitate of silver allylide is formed. These 

 precipitates are highly explosive after separation and drying, a 

 temperature of 150° being sufficient to bring about their ex- 

 plosion. When they are treated with dilute nitric or hydro- 

 chloric acids they dissolve with evolution of allylene. Ethyl 

 alcohol behaves similarly towards heated magnesium, and the 

 black residue left in the boat after the completion of the reaction 

 is similarly decomposed by water with liberation of allylene, 

 the rapidity of evolution of the latter being also largely 

 augmented by the addition of a little ammonium chloride. 

 The most convenient' alcohol to employ, however, is propyl 

 alcohol, for the black m.agneiium residue is in this case decom- 

 p osed much more rapidly by wa'er at the ordinary temperature, 

 and the yield of gas is considerably larger. Prof. Keiser states 

 that this method of preparing allylene for lecture purposes, by 

 the reaction between magnesium and propyl alcohol, and 

 subsequent decomposition of the product by water, is far 

 preferable to the ordinary method of decomposing propylene 

 bromide with alcoholic potash. Most of the other alcohols 

 likewise afford magnesium residues which liberate allylene when 

 brought in contact with water, but the gas is rarely so pure as 

 that derived from the use of propyl alcohol. 



The additions to the Zoological Society's Gardens during 

 the past week include a Macaque Monkey {Macactis cyno- 

 molgus, S) from India, presented by Mrs. Turner-Turner ; an 

 Azara's Fox [Canis azai;,'] from Brazil, presented by Messrs. 

 Edgar and Harold Turner ; four Amadavade Finches [Estrelda 

 amaiiiava) from India, presented by Mrs. Faulkenor ; a 

 Chukar Partridge {Caccabis chukar) from India, deposited ; a 

 Sykes's Monkey {Cercopithecus albigiilaris, 9 ) from East Africa, 

 two Red-crested Pochards (Fuligula rufina, i 9 ) from India, 

 purchased ; a Great Kingaroo (Macropis gigaiileus, i), three 

 Hunter's Spiny Mice (Acomys hunleri) born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 Spectrum of the Okion Nebula. — A full account of the 

 photographs of the spectrum of the Orion Nebula, which were 

 taken with Mr. Lockyer's 3oinch reflector at Westgate-on-Sea 

 in 1890, has just been published in the Philosophical Trans- 

 actions (vol. 186 A, p. 73.) Four hydrogen lines more refran- 

 gible than K are shown on the photographs, and in all S4 ''"es 

 have been recorded. The line near wave-length 3730, first 

 discovered by Dr. Huggins, is a very strong Ime, and among 

 other prominent lines, is the well-known chromospheric line at 

 wave-length 4471. It is shown that many of the principal lines 

 are coincident with bright lines photographed in the spectrum 

 of P Cygni at South Kensington, and with bright lines in plane- 

 tary nebulae and bright line-stars photographed by Campbell 

 and Pickering, so that a close connection of these bodies is 



