-62 2 



NA TURE 



[OCTOHER 29, I< 



nepliew. I imagine il nnisl bo somewhat different to Mr. 

 KiclMlale's specimen, jiulgini; from the variations of colour. 

 Tliis one lias green as its predominant colour, changing in a 

 l)right light to a brown or almost chocolate hue, and at night it 

 is often a bright canary yellow, especially when kept, as it was 

 on its first arrival, in a cage which was painted cream colour 

 inside. Only once have I seen it turn white, and that was when 

 i was just in time to save it from being killed by a cat, and then 

 I suppose it was the result of fear. It frequently has yellowish 

 stripes running along its body, and sometimes round red spots. 

 Not unfrequently one side of its body is of a different colour to 

 the other. It drinks only sparingly, but I saw it do so this 

 morning, putting its head right into the glass with which it is 

 supplied. 



After it had been in England about a year it surprised us by 

 laying some eggs, and has done so again within the last few 

 months. The eggs are roundish, about the si/e of small peas, 

 and iif a clear orange colour, somewhat resembling grains of 

 maize. If either Mr. Kidsdale or Mr. Bartlett would like to 

 have one, I should be pleased to send them specimens. 



The last time it changed its skin it had the misfortune to lose 

 about half an inch of its tail, from what cause I am unable to 

 say, and this has made it much less able to get about, as the loss 

 deprived it of the little hook at the end of the tail with which it 

 used to cling to the sticks on which it climbs. I never saw it 

 try to help the skin off with its feet, and it has generally come 

 off in flakes, taking a fortnight or so over it. 



I think the most extraordinary thing about the reptile is the 

 wonderful way in which the two eyes work quite independently 

 I if each other, and enable it to survey comfortably objects in quite 

 opposite directions. A. Alex. Blakisto.n. 



Glastonbury, October 21. 



Chameleons at the Zoological Society's Gardens. 



Mr. RinsD.-iT.K must have mistaken Mr. Bartlett when he states 

 (Nature, October 15) that there are no Chameleons in the 

 Zoological Society's Gardens. We are seldom, if ever, without 

 examples of these reptiles, and at the present moment have five 

 specimens, three of Chamcko vulgaris from North Africa, and 

 two of Chanieko pumiliis from the Cape. At various times 

 we have exhibited specimens of eight species of Chameleonida;. 

 I may add that Chameleons generally do not do well in captivity, 

 and require constant attention. P. L. Sci.ater. 



3 Hanover .Square, I^ondon, W. , October 22. 



The Organisation of Technical Literature. 



The *' Catalogue of Scientific Papers," compiled and pub- 

 lished by the Royal Society of London, was intended to serve 

 as an index to the titles and dates of scientific papers con- 

 tained in the Transactions of societies, journals, and other 

 periodical works. This Catalogue is highly valuable to all 

 technical inquirers, and it is a matter of deep regret that the 

 International Conference, held under the auspices of the Royal 

 .Society of London, has decided that the International Catalogue 

 of Scientific Literature, which is to begin with 1900, is to relate 

 to pure science only, applied science being strictly excluded. It 

 is possibly too late to remedy the position, which is probably 

 lue to the absence of representatives of technical societies at 

 the International Conference. 



It would .seem desirable, further, that there should be a con- 

 ference of technical societies to discu.ss the publication of a 

 iubject-matter index to technical and scientific periodicals. 

 The Federated Institution of mining engineers has had for some 

 time before it the question of the publication of such an index 

 of subjects of interest to mining and metallurgical engineers ; 

 and probably a comprehensive index to engineering and other 

 technical papers would prove more valuable. 



This suggested conference of technical societies might also 

 consider other questions which interest technical societies 

 individually, but which they are unable to obtain owing to 

 want of concerted action. Thus, such an association might 

 approach the Government on .such questions as the excessive 

 cost of postage of Transactions, as there can be no valid reason \ 

 why they should not be placed in the same position — although \ 

 their Transactions are issued at varying intervals of time — by a I 

 short Act of Parliament, as an ordinary weekly newspaper. 



And there are many other matters, which no doubt crop up 

 in connection with the carrying out of the objects of individual 



NO. 1409, VOL. 54] 



societies, in which concerted action would produce valuable 

 results. M. Wai.ion Brown, Sicrctmy. 



Neville Hall, Newcastle-upon-Tyne, October 21. 



A Mechanical Problem. 



.\ MAN stands in a box, whose si<les, fioor, and top are rigid 

 and inelastic, the box itself being light as comjiared with the 

 weight of the man, and a few inches higher than himself. The 

 man jumps, and .strikes the roof with his hands or head. 



Is it possible for him to raise the box in this way (even in a 

 small degree) perpendicularly from the ground ? 



"Cromerite." 



l(l) The box rests on the ground. Therefore the downward 

 push of the man on the box on springing is balanced, and no 

 more affects the motion of the box than if his feet rested on the 

 ground. If his muscular force were great enough, he could give 

 infinite velocity to his body. He is now moving, the box still 

 at rest as before. When his head strikes the top, the rate of 

 destruction of his upward momentum is the upward force on 

 the box, and this depends on the elasticity of his head. If his 

 head is rigid enough he lifts the box, however heavy it may be. 



(2) The " argument waged round " the question is possibly 

 based on the idea that the box and man are in free space. In 

 free space, nothing that the man can do will affect the motion 

 of the centre of mass of the whole system (the box-man .system) ; 

 but the box itself moves, so that even in free si)ace "' the man 

 moves the box." — J. P.] 



Extension of the Visible Spectrum. 



While engaged on work in connection with the di.scharge 0. 

 electrification by ultra-violet light, we have come across a fact 

 which it may be convenient to state by itself, viz. that the spec- 

 trum of an arc can be made visible over the greater part of its 

 immense range of action on electrified metals, by receiving it 

 upon a screen of the double fluoride of uranium and ammonium, 

 such as is frequently used for displaying X-rays. The arc- 

 light must, of course, be passed through a quartz train, and a 

 long arc is best, especially an arc containing aluminium : but 

 under these circumstances, vvhereas the ordinary visible spectrum 

 may be three-quarters of an inch broad, a breadth which may 

 be doubled or trebled by the use of ordinary fluorescent sub- 

 stances, the spectrum received upon a uranium screen is five 

 inches broad, and is full of bright line.s. 



Suitable screens are supplied by Ducretet of Paris, or by 

 Chadwick of Manchester, or they can be readily made ; and any 

 one possessing either a Rowland grating, or a quarter prism and 

 lens, can try the experiment. 



It is just possible that it has not been noticed, to the full 

 extent, before. Oliver J. Lodge. 



Liverpool, October 26. Benjami.n Davies. 



ON THE COM.^rCNICATION OF ELECTRICITY 



FROM ELECTRIFIED STEAM TO AIR} 

 'T^HE e.xperiment described in this paper was a first 

 -'■ slight instalment of an investigation, which we 

 have proposed to make, of the difftision of electricity 

 through air, and the communication of electricity from 

 the molecules of one gas to the molecules of another 

 beside it or mixed with it. 



By arrangements, readily imagined, we electrified dry 

 superheated steam at atmospheric pressure by a needle- 

 point connected with an electric machine. The dry 

 electrified steatii was drawn off through a tube with an 

 inlet admitting unelectrified air to mix with the steam. 

 The mixed air and steam were drawn off through the 

 metal worm of a still, and cooled by an abundance of 

 cold water around the worm. The condensed water fell 

 into a Wolffs bottle, in one neck of which the exit tube 

 of the worm was fixed. The air, thus cooled and partially 

 dried, was drawn out of the other neck of the Wolffs 

 bottle through a drying tube of pumice and sulphuric 

 acid ; and thence through a short paraffin tunnel to one 

 of our electric filters," insulated and connected with the 



1 Al).;ii-.. If iiiiinih ation to Section .\ of tlie British .\ssociation at 



Uverpo..] (- i .::,! : ,1. by Lord Kelvin, G.C.V.O., K.R.S., M:igi.us 

 M:.oUMn, ., ,, \l , :!. r.ali. 



^ "On 111. I 11 .. I. . mill ation of Air," Prof. K.S., M:irch 1875. 



