3H 



NATURE 



[November 20, 1919 



and that, in the processes of smoothing, the horizontal 

 movement is required to force the abrasive grains 

 against the sides of the cavities. From actual tests it 

 is found that the rate of abrasion is directly proportional 

 to the pressure and to the relative speed of translation. 



James Weir French. 

 Anniesland, Glasgow, October 13. 



The Breeding of the King Penguin. 



The Zoological Park at Edinburgh has had the 

 good fortune to possess, almost from its inception, a 

 small group of king penguins. Three of the birds 

 were receifcd in January, 1914, from South Georgia, 

 a second consignment, of which three survived, arriv- 

 ing in the spring of 1917. A hope was excited that 

 they might breed when two of them were observed to 

 be mating in the autumn of 1915, but nothing further 

 occurred at that time. In the late summer of 1917 

 one of the birds became broody, and sat in the posture 

 of incubation for about a month, but no egg was 

 apparently laid, nor was this bird one of the two 

 which had been observed to be paired. It was not 

 until 1918 that the paired birds really settled down in 

 earnest, and much interest was aroused when, on 

 July 8 of that vear, one of them was found to have 

 an egg. 



The king penguin, like its near relative the emperor 

 penguin, makes no nest, but carries the single egg on 

 its feet, where it is . held in place and covered for 

 warmth and protection by a fold of the skin and 

 feathers of the abdomen, which, being furnished with 

 a constricting muscle, grips the egg tightly. The 

 brooding penguin can not only travel about with the 

 egg in position, but even scratch its head with one 

 foot while still holding the egg securely. Both 

 sexes share in the work of incubation, the transfer 

 of the egg having been observed on the second dav. 

 The parental instinct is very strong in the king 

 penguin, not only in mated, but in the unattached 

 birds as well. The group at this time contained three 

 other birds, and their presence, or perhaps nothing 

 but the very obvious conflict of desire for simultaneous 

 possession of the egg between the husband and wife, 

 may have been the cause of the misfortune which 

 followed; at any rate, it was disappointing to find, 

 after about two weeks, that the egg had been broken 

 and that its custodian was believed to be relieving 

 the tedium of duty by occasionallv sipping its contents. 



The floor of the enclosure consists of shelving rock, 

 and to reduce the risk of breakage if an egg were 

 produced this year, a large bed of sand was laid down. 

 The next incident was again disappointing, for in July 

 an egg was laid, but within an hour or so it had dis- 

 appeared. a'Vs none of the birds showed any disposi- 

 tion to incubate it, I formed the opinion that it had 

 been laid by one of the unmated birds, and this 

 seemed to be confirmed when, on September i, the 

 female of the pair was found to have an egg. The 

 other three birds were at once removed from the en- 

 closure so that thev should not interfere, and for two 

 days all went well, the male bird taking the egg at 

 night and the hen during the day. On the third dav, 

 however, the calling of one of the other birds — the 

 third of the three originally imported- — seemed to dis- 

 turb the male, and he left his wife, refused to have 

 anything more to do with the egg, and spent the day 

 (and probably the night) in calling to the third bird 

 pnd trying to get to it. .'Xfter some days, as the 

 female seemed to be suffering from the unrelieved 

 care of the egg, and neither bird would feed, it was 

 decided to put the third bird back. When this was 

 done they all settled down together, and the male 

 NO. 2612, VOL. 104] 



resumed his share in the labour, the third bird usually 

 standing near. 



The time during which each bird had the egg 

 varied from a day to a week or more. The female 

 when she had the egg always remained in the same 

 place, where she made a slight hollow in the sand, 

 but when the male had it -he occasionallv went for a 

 walk round the enclosure, shuffling along with the 

 egg on his feet. He even descended from one ledge 

 of rock to another by turning round and working 

 himself down backwards — a performance which led 

 to several narrow escapes for the egg. 



As the period of incubation elapsed the result was 

 awaited with some anxiety, and it was in no small 

 degree gratifying to find, on October 22, that the 

 egg was chipped and the chick inside alive. It was 

 not, however, until two days later that the chick was 

 clear of the shell, the period of incubation thus being 

 seven weeks and four days. The chick when hatched 

 was comparatively small, and the skin was bare, but 

 in a few days it increased considerabK- in size. The 

 young bird, like the egg, is kept between the feet 

 of the parent and covered by the fold of skin ; it is 

 fed at frequent intervals with semi-digested fish dis- 

 gorged by the parent. As in the case of other birds 

 which feed their young by this method, the chick 

 places its head in the parent's mouth and takes tb; 

 food from the gullet. 



Apart from accident, there seems every likelihood 

 that the young bird will be reared. It may be claimed 

 which feed their young by this method, the chick 

 king penguin has bred outside those islands of the 

 Antarctic seas on which it has its home, and the 

 record is a unique one. T. H. Gillespie. 



Zoological Society of Scotland, Edinburgh, 

 October 29. 



A Helium Series In the Extreme Ultra-Violet. 



It has been shown that the helium series first dis- 

 covered in a terrestrial source by Fowler can be repn;- 

 sented bv the formula 



V = 1097 50 ( «i 



(?)*"(?)■ 



where n^ has the value 3 or 4 (Evans, Fhil. Mag., 

 vol. xxix., p. 284, 1915). 



If fj, be given the value 2, and n^ the successive 

 value 3, 4, and 5, lines result at wave-length 1640-1, 

 1214-9, ""d 1084-7. My previous investigations of the 

 helium spectrum did not afford much evidence as to 

 the existence of these lines {Astrophys. Journ., 

 vol. xliii., p. 92, 1916); a recent search, however, has 

 been more successful. With a powerful disruptive 

 discharge in helium, a sharp, fairly strong line appears 

 at 1640-2; no trace of it is_ found in hydrogen under 

 the same electrical conditions, and it does not occur 

 in helium when the discharge circuit is free from- 

 capacity. Under the same violently disruptive condi- 

 tion the line at 1216, always present in helium and 

 hydrogen, develops a satellite on its more refrangible 

 side ; this satellite is not well resolved, but its wave- 

 length appears to be about 1215-1. The region that 

 should be occupied by 1084-7 's obscured by a strong 

 pair at 1085, probably due to an impurity. 



Owing to the difficulties of vacuum spectroscopy, it 

 is perhaps unwise to claim that the evidence in this 

 case is conclusive. 1 regard it as very probable, how- 

 ever, that two members of this series in helium have- 

 been found in the extreme ultra-violet. 



Theodore Lyman. 



Harvard University, October 25. 



