December 19, 1907] 



NATURE 



149 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



The International Memorial Statue of Lamarck. 



T[iE sub.scription list for the purpose of erecting a statue 

 of tliR great French naturalist Lamarck in the Jardin des 

 riantes, Paris, where he did much of his work, will shortly 

 be closed. 



English men of science will, it is hoped, realise that 

 it is now time to send subscriptions in order to show their 

 regard for the memory of the great man whose name 

 stands by the side of that of Darwin as a philosophical 

 naturalist. 



Subscriptions of any amount may be sent at once to 

 me at the Natural History Museum, Cromwell Road, 

 S.W. ; their receipt will be acknowledged, and the subscrip- 

 tions sent to the committee of French naturalists who are 

 collecting funds, and will issue a list of subscribers ; or 

 subscriptions may be sent direct to Prof. Edmond Perrier, 

 director of the museum, Jardin des Plantes, Paris. 



E. Ray Lankester. 



British Museum (Natural History), Cromwell Road, 

 London, S.W. 



Mulattos. 



May I have a line to correct Sir William Thiselton- 

 Dyer's impression (p. 126) that the tragic story of The 

 Pure White Mother and the Coal-black Babe was accepted 

 % by me " as accurate and in perfect good faith "? I sup- 

 pose I ought to have underlined the gentle sneer at a 

 blackness transcending the natural blackness of a negro 

 baby. At any rate, I told the anecdote simply to illus- 

 trate the nonsense people will talk under the influence of 

 race mania, and I hope it will not be added too hastily 

 to the accumulation of evidence on the Mendelian side. 



H. G. Wells. 



Nest Eggs of Platypus. 



Mv attention has been directed to the review of Mr. 

 le Souef's book on " Wild Life in Australia " (Nature, 

 October 24) and to the reviewer's subsequent note on the 

 eggs of Platypus (N.ature, November 28). The reviewer 

 states that there " appears to be no definite evidence that 

 the eggs " of Platypus " are really laid entire." .As I had 

 the good fortune to find some in that condition a few years 

 ago, I think it well to record the fact. I have already 

 shown these eggs in Sydney and to the British .Association 

 (1899), the Royal Society of Edinburgh, and other scientific 

 bodies, but, alas ! I have not found time to write a full 

 account of my material, and I have been putting off — 

 perhaps too long — in the hope of getting sufficient leisure 

 for the task. 



In September, 1897, I visited Gayndah, in Queensland, 

 in search of the ftggs of Ceratodus and Platypus. I had 

 at once abundant success as regards the Ceratodus 

 material, and so was tempted to devote most of my time 

 to it. I shot a few specimens of Platypus, however, and 

 did a little digging for eggs, without finding any. I did, 

 nevertheless, have success of a kind with Platypus. On 

 tile last day of my fortnight in the district (September 20) 

 I managed to find a nest with an adult female Platypus 

 and a young male 5^ inches in extreme length. The mode 

 of finding was both interesting and instructive. My two 

 men and I, after trying several burrows in vain, came 

 on the productive one. -After following it for about 10 feet 

 we rc.iched the " breathing hole "; after another 7 feet we 

 came to an apparent end of the burrow, and were greatly 

 disappointed, as we had seen clearly the wet and inwardly 

 directed footprints of a Platypus all the way from the 

 external opening. One of the men groped about eagerly 

 for any sign that the Platypus was working away from 

 us, and finally we were able to track the burrow — filled 

 though it was — through the hard surrounding soil. It 



NO. 1990, VOL. 77] 



soon appeared that the tube had only been blocked for a 

 short distance by loose soil, which was doubtless of use 

 in keeping out intruders. After a short distance we got 

 beyond tlie plug, and came again to an open passage. 

 Fully 21 feet from the bank we came upon the nest. It 

 was just large enough to permit of the adult Platypus 

 turning in it. The top was about 9 inches above the 

 bottom, and was about a foot from the surface of the 

 soil. The nest itself was made of bark, leaves, &c. The 

 mother and her offspring were quite buried in the material 

 of the nest. 



In 1898 I was again able to spend a few days in 

 Gayndah, and I secured several uterine eggs from Platypus 

 and three entire nest eggs. On August 31 I got two nest 

 eggs adhering together, each of them about 15 mm. in 

 greatest diameter. The eggs were perfectly intact, and 

 the shells firm. The embryos were far advanced, and 

 measured about i cm. in length. 



On September i I got another intact nest egg and a 

 female adult at the end of a burrow. The embryo in this 

 egg was even more advanced than in the others. 



I secured about the same time several nest embryos, and 

 I was inclined to think that my visit was rather late in 

 the vear for nest eggs. 



I may" add that, as a rule, in following a productive 

 burrow I had to work through one or several "plugs." 

 It would seem as if the mother Plat5-pus, even when at 

 home, adopts the same method of securing safety as rabbits 

 make use of when leaving their voung in a burrow. 



Queen's College, Belfa'st. Gregg Wilson. 



Sulphur as an Insulator. 



The gold-leaf electroscope, simple as it is, has proved 

 itself to be an excellent instrument for showing the proper- 

 ties of statical electricity ; but usually it has this drawback, 

 namely, that it does not retain an electrical charge at a 

 constant value for a conveniently long period of time. 

 Recently an aluminium-leaf electroscope has been tested 

 by me for insulation ; the results, which speak for_ them- 

 selves, may be of interest to others who employ this elec- 

 trical instrument. The electroscope was designed by Prof. 

 J. S. Townsend, F.R.S. Its excellence depends on the 

 metal leaves being supported by means of sulphur. The 

 appended table shows how it behaved during ten days, on 

 many of which rain fell, and from the air in the room 

 where the experiment was made moisture was freely 

 formed on bottles and metal instruments. Each division 

 indicates a potential difference of too volts. The charge 

 was positive ; * indicates rain : — 



I have also a quadrant electrometer having a long 

 suspension of metal ribbon. All parts of this instrument 

 are supported on pure sulphur ; an experience lasting over 

 many years has proved the excellence of sulphur as an 

 insulator. Of course, an instrument so constructed requires 

 careful handling, but when once erected in a suitable 

 niche it will be found to give hardly any trouble and to 

 keep its charge well. It seems somewhat strange that 

 with some few and noteworthy exceptions, sulphur as an 

 insulator should not be more frequently employed in the 

 physical laboratory at the present day, as its excellent 

 qualities were known and utilised in the early days of 

 electrical science before 1797 by Wilcke, Oipinus, Henley, 

 and others. I may add, in conclusion, that in the con- 

 struction of the ' interesting little electrical dry pile 

 apparatus, whereby a small bell has been constantly struck 

 for forty-two years in the Clarendon Laboratory, Oxford, 

 sulphur was employed as the insulator. 



F. J Jervis-Smith. 



