36 



NATURE 



[November 12, 1891 



One very interesting point we may note with regard to 

 the class Aves— namely, that while birds still possessed 

 the teeth which they had inherited from their reptilian 

 ancestors, two very remarkable and distinct types of the 

 class had already made their appearance, and that these 

 two types have persisted on, even to the present day, 

 dividing the class mto Naiit<.c and Lurinaice. 'llie cha- 

 racters of the ancient toothed birds indicate undoubtedly 

 a great antiquity for the class, which w as probably evolved 

 from the Reptilia in Triassic times, or even earlier. 



Although the majority of entries in Mr. Lydekker's 

 Catalogue relate to the Carinatce, the Ratitce are also 

 well represented in the collection, and there is a sufficient 

 number of remarkable extinct forms and figured types to 

 impart to this volume a high scientific interest. 



In conclusion, we must express our thanks to Mr. 

 Lydekker for this last contribution to the very useful 

 series of Catalogues which he has prepared for the 

 Trustees of the British Museum, which cannot fail to 

 prove of great service to biological science. 



IRON CARBONYL FROM WATER GAS. 



A T the meeting of the Chemical Society on Thursday 

 -^~*- last, November 5, a communication was made by 

 Sir Henry Roscoe, M.P., in the joint names of himself 

 and Mr. Scudder, concerning a new and highly interest- 

 ing mode of formation of iron carbonyl, Fe(C0)4, the 

 volatile compound of iron and carbon monoxide in- 

 dependently obtained a few months ago by M. Berthelot 

 and by Messrs. Mond and Quincke. During the course 

 of experiments upon the application of water-gas, which 

 contains about 40 per cent, of carbon monoxide and an 

 approximately equal quantity of hydrogen, to the purposes 

 of illumination, it was noticed that the magnesia combs 

 placed over the flame of the burning water-gas rapidly 

 became coated with oxide of iron, which materially 

 lessened the illuminating power. Steatite burners were 

 likewise found to become stained with oxide of iron. The 

 deposit, when allowed to accumulate, took a coralloid 

 tuberous form quite different from accumulationsof particles 

 mechanically carried in a stream of gas This led to the 

 supposition that the iron had existed in the water-gas in 

 a volatile form, and was deposited as the result of the de- 

 composition of the volatile compound at the high tem- 

 perature of the flame. Further experiments were 

 subsequently made with water-gas which had been 

 compressed to eight atmospheres in iron cylinders. After 

 standing for a week in such a cylinder, the gas, which 

 usually burns with a blue non-luminous flame, was found 

 to burn with an intensely yellow flame, and the illumin- 

 ating power when the magnesia comb was placed over 

 the flame was considerably reduced, owing to the de- 

 position upon the comb of large quantities of oxide of 

 iron. The experiment was repeated before the Fellows 

 of the Society present, and upon depressing the lid of a 

 porcelain crucible upon the flame a black stain was im- 

 mediately produced, due to the deposition of particles of 

 metallic iron or oxide. Moreover, upon heating the glass 

 tube through which the gas was passing upon its way to 

 the burner, a black mirror of metallic iron was rapidly 

 formed. A thick deposit was also formed upon a plug of 

 cotton-wool inserted in the tube between the heated 

 portion and the burner. A similar tube was exhibited, 

 through which, while heated, one cubic foot of 

 water-gas had been allowed to pass from a cylinder in 

 which it had been stored two weeks ; the deposit was 

 strikingly large, both in the portion which had been 

 heated and upon the cotton-wool. After allowing a 

 similar cylinder containing compressed water-gas to 

 stand for five weeks, the flame was found to be smoky, 

 from the large amount of iron liberated during the com- 



NO. I 1 50, VOL. 45] 



bustion. The smokiness, and, indeed, the whole lumi- 

 nosity, disappeared upon heating the tube, the gas burning 

 with its ordinary blue flame ; a thick mirror was at once 

 deposited, and a large amount of iron retained by the 

 cotton-wool. Thirty litres of gas from this cylinder, 

 burnt during the space of half an hour, gave thirty-two 

 milligrams of metallic iron in the form of a mirror, and 

 forty milligrams were deposited upon the cotton-woo'. 

 Upon passing the gas through a U tube surrounded by 

 ice, a few drops of a turbid liquid were obtained, consist- 

 ing mainly of iron carbonyl, possessing the properties 

 ascribed to it at the meeting of the BritisTi Association at 

 Cardiff by Mr. Mond. The turbidity^ntirely disappeared 

 upon the addition of hydrochloric acid. From the 

 above experiments it is evident that iron carbonyl 

 is produced in the cold by the action of the 

 carbon monoxide contained in the water-gas upon 

 the iron of the containing cylinder, for the greater 

 the length of time during which it has been stored, the 

 greater is the amount of the compound present It is 

 interesting to learn that the same deposit of metallic iron 

 or oxide is found upon steatite burners from which ordi- 

 nary coal-gas is burnt, pointing to the existence of iron 

 carbonyl in our common illuminating gas. This conclu- 

 sion is strengthened by the fact recorded by Dr. Thome, 

 that coal-gas which has been compressed in iron cylinders 

 and allowed to stand some time is rendered unfit for use 

 for lantern projection, owing to the deep stain of iron 

 formed upon the lime cylinders. It is also interesting, in 

 view of the fact that iron carbonyl is capable of formation 

 in the cold, to note that the nickel compound, Ni(C0)4, 

 described by Messrs. Mond, Langer, and Quincke last y^r 

 {vide Nature, vol. xlii. p. 370), is also readily formed in 

 the cold, provided the metallic nickel has been previously 

 heated in a current of hydrogen. A. E. Tutton. 



CAPE GUARDAFUI AND THE NEIGHBOUR- 

 ING SEA} 



'HPHIS work consists of monthly charts which illustrate 

 -*■ the sea surface temperature, the wind, ocean cur- 

 rents, sea disturbance, and weather in the immediate 

 vicinity of Cape Guardafui, extending down the Somali 

 coast so as to include Ras Hafiin, and covering the sea to 

 53^^ E. Some years ago the Admiralty issued a " Notice to 

 Mariners," indicating the precautions necessary in round- 

 ing Cape Guardafui from the southward, in consequence 

 of the Committee of Lloyd's having drawn attention, 

 through the Board of Trade, to the large number of 

 wrecks which had taken place in the neighbourhood. It 

 was pointed out that the wrecks occurred chiefly during 

 the period of the south-west monsoon, which blows from 

 April to September, when the weather on the African 

 coast is stormy and accompanied by a heavy sea ; the 

 currents are strong, and the land is generally obscured 

 by a thick haze. The principal recommendation adopted 

 by the Admiralty was the necessity for every precaution 

 in verifying the vessel's position by soundings : and with 

 this precaution it is asserted that the vessel's safety is 

 assured, as the water rapidly deepens northward of the 

 parallel of the cape. Ignorant of the exact position, 

 many seamen have mistaken the high land at the back 

 of Ras Jard Hafiin, ten miles south of Cape Guardafui, 

 for the latter, which, being lower and lighter in colour, is 

 often invisible at any considerable distance. Believing 

 the cape to be passed, ships have been steered into the 

 comparatively low bay between the two headlands, and 

 have struck on the sandy beach before any warning has 



' " Meteorological Charts of the Portion of the Indian Ocean adjacent to 

 Cape Guardafui and Pas Hafiin." (London: Publiihed by the authority 

 of the Meteorological Ccuncil, 1891.) 



