July, 1905.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



159 



the same extent as now, she has five centuries before her, and 

 during this period it may safely be said that no one will feel 

 the t^radual exhaustion which will be taking place. But the 

 Commissioners point out in their report what other thought- 

 ful men have pointed out before, that other considerations 

 will come into play which will probably have the effect of 

 reducing the rate of increase of output, until finally the 

 immense existing output will actually decline. Not im- 

 probably by the time that our coal supplies are approaching 

 exhaustion, the greater portion of the demand will have 

 ceased, and other means of lighting and heating will exist 

 other than that to be obtained from coal. 



Foreign Coal. 



When we look at deposits of coal which are found abroad 

 we may be fairly astounded at the wealth which some conti- 

 nental countries possess, and it is as well that there should be 

 a clear understanding that the foreign supplies of coal bear 

 much the same proportion to our British supplies as an 

 elephant does to a mouse. No human agency can ever ex- 

 haust the world's supplies. But frequently they are so situated 

 as to be practically valueless. They are in a similar category 

 to what the Commissioners called the " unproved " coalfields 

 of Britain, and the seams at depths greater than 4000 feet, 

 below which no mine is known to exist. China has rich 

 possessions of coal. Many of the seams are near centres of 

 population, and are easily worked. In the mountainous areas 

 of western China coal-measures are found in great profnsion, 

 and seams from 30 feet thick and upward have been traced in 

 a horizontal plane for 200 miles towards the Mongolian fron- 

 tier. But at present they are practically valueless, and, like 

 our own deep-lying seams, require engineering skill such as is 

 not now to be found for their development. 



The Age of Diplodocus. 



At the official presentation to the Natural History Museum 

 of the replica of Diplodocus Canuxii-, the curator of the Car- 

 negie Museum was reported to have alluded to the age of the 

 monster Dinosaur as four thousand centuries. English geo- 

 logists do not as a rule care to speak of the age of any par- 

 ticular formation or fossil in terms of years. Years are such 

 insignificant items where geological ages are concerned, and 

 every estimate so made is certain to be open to very great 

 error. But it is impossible to conceive by what means of cal- 

 culation a creature of Jurassic age can be said to be but 400,000 

 years old. Geologists have for years fretted under the reign 

 of those physicists who say that no form of life was possible 

 on this earth before 100 millions of years ago. And in view of 

 possible discoveries in connection with radio-active bodies in 

 the future, it becomes increasingly difficult to place a period 

 either to the time at which the sun began to give out heat, or 

 when it will cease to do so. Geologists will, I am convinced, 

 find themselves compelled to tear themselves away from all 

 restrictions of time placed upon them by those who are first 

 physicists and after geologists. The more the facts of geology 

 are borne in upon one, the more, as it seems to me, is it 

 impossible to see the possibility of all the great geological 

 phenomena having taken place in less than 250 millions of 

 years. By a process of calculation on this basis, the age of the 

 Diplodocus, namely, the Jurassic age, came to a close 415 mil- 

 lions of years ago. This is, however, only an estimate ; but it 

 is likely to be .nearer the truth than the utterly insufficient 

 number of years previously given. 



ORNITHOLOGICAL. 



By W. P. Pycraft, A.L.S., F.Z.S., M.B.O.U., &c. 

 The Habits of the Kagu. 



The Kagu (Rhinociicctus juhatus) is one of those rare and 

 aberrant types which seems likely to disappear from off the 

 face of the earth, leaving but little save its skin and a few 

 particulars of its anatomy for the ornithologist of the future 

 to remember it by. Though a native of New Caledonia, 

 according to some, its nearest ally is the equally rare and un- 

 known Mesites or Madagascar Kagu, while others regard it as 

 more nearly related to the Sun-bird [Eurypga helias) of South 

 America, This, too, is an aberrant type. 



All that appears to be known of its eggs and nesting 

 habits we owe to observations made on a pair of these birds 

 in captivity and recorded in the current number of the Emu. 

 A pair, kept in an aviary at Sydney, built a nest of a few 

 coarse sticks and leaves, in which was laid a single egg. This 

 was then surrounded by more sticks and brooded continually 

 by the cock bird, relieved occasionally, it is believed, and 

 during the night, by the female. Incubation lasts five weeks. 

 If the egg be removed, another is laid, and this will be 

 replaced, if taken away, two or three times. The egg is here 

 described as bearing a striking resemblance to that of a gull, 

 from which it differed only in the fine texture of the shell. 



This is curious, inasmuch as an egg dropped by one of these 

 birds in the Zoological Gardens in London, and now in the 

 British Museum, bears as close a resemblance to that of the 

 Southern Courlan (A ramus scolopaceus), being perfectly elliptical 

 in shape, cream-coloured, spotted and blotched with dark 

 brown and purplish grey. It differs from the Courlan's egg, 

 however, in being without gloss, and slightly rough in texture. 



The Hunting Tactics of the Sea Eagle. 



A writer in the Field (June 17) gives a short but interesting 

 account of his observations on the habits of the white-tailed 

 Sea Eagle (Haliictus albicilla) in Greenland. In summer its 

 principal food is salmon, varied by sea-birds common along 

 the inlets. In autumn, when the salmon have ascended to the 

 lakes, the birds resort to the sea. They appear to have a 

 special fondness for eider duck, which are taken by strategy. 

 " Stationed near the water in a commanding position, with a 

 background of cliff, the colour of which assimilates with that 

 of the eagle's plumage, he sits motionless, until a flock of duck 

 settles near him. After a time one or two dive in search of 

 food, but not until all have gone under together does the eagle 

 make a sign. He then glides swiftly to the spot, and circles 

 over it close to the water ; with his sharp eye he can detect 

 the birds before they reach the surface. At first he is not 

 usually successful, for as soon as they become aware of the 

 presence of the enemy, they dive again instantly; but in time 

 they are obliged to come up for air, and then one of them 

 becomes an easy victim." A full-grown eider drake is easily 

 lifted up and borne away in the talons of this powerful pirate. 

 Most of the sea-fowl, it is interesting to note, readily dis- 

 tinguish between the Sea-Eagle and the falcon when on the 

 wing and vary their tactics, and escape capture accordingly. 

 Thus, when pursued by the falcon they dive, but in fleeing 

 from the eagle they depend on their ability to turn rapidly on 

 the wing, which the eagle is unable to do. 



Golden Orioles in Stratford. 



Mr. Reginald Hudson, in Nature A'o/c'sfor June, records the fact 

 that a pair of Golden Orioles were seen in a garden on 

 April 27, at Shottery. Whether they have so far been allowed 

 to remain unmolested, we cannot say ; if they have, in all 

 probability they will nest here. As many readers are 

 doubtless aware, the Golden Oriole has more than once 

 reared its young in these islands, and were they not so 

 mercilessly shot down on every occasion, these gorgeous birds 

 would doubtless more frequently visit us. 



Iceland Gull in the Moy Estuary. 



Mr. R. Warren, in a somewhat sarcastic note in the Irisli 

 Naturalist for June, records the fact that an immature Iceland 

 Gull, Laruslcucoptcrus, was shot by himself in the Moy Estuary 

 on April 26. He gives the following measurements: — 

 Length, 2\\ Ins.; capus, 16 ins.; tarsus, 2 ins. 



Tufted Duck Breeding in Co. Mayo. 



."Xccording to the Field (June 17) : Three or four pairs of 

 Tufted Ducks, Fuligula cristata, appear to be breeding this 

 year on Lough Conn, where a nest of eleven eggs was seen by 

 Mr. S. Scroope. The nest was identified by a piece of down 

 sent by the Editor of the Field to Mr. Whittaker, of Rain- 

 worth. Thus the extended breeding range of this bird in Ire- 

 land, to which Mr. Ussher has drawn attention (Birds of 

 Ireland), is confirmed. In the volume just referred to, it is 

 stated that the portions of Ireland where this bird is not 

 known to breed include, amongst others, " the province of 

 Counaught west of the Shannon, and Lough Arrow, in Sligo." 

 Lough Conn lies a little less than 30 miles from Lough Arrow. 



