December io, 1891] 



NATURE 



133 



is not really much more difficult than the dressing of a 

 child for church. The most remarkable part of the 

 process is the painting of the forehead, trunk, and ears, 

 which follows a thorough washing. " The designs are 

 often good, and the whole serai, excepting always the 

 elephant himself, is deeply interested. His mind and 

 trunk wander ; he trifles with the colour-pots ; so with 

 each stroke comes an order to stand still. Some mahouts 

 are quite skilful in this pattern work." 



In an interesting chapter on the training of animals, 

 Mr. Kipling shows that the skill of the natives of India 

 in this difficult art has often been greatly overrated. The 

 Oriental brings " boundless patience " to the task, but 

 " he has no steadfastness of aim, nor has he sufficient 

 firmness of hand and will to secure confidence and 

 obedience." The cheetah or hunting leopard {Felts 

 iubata), when caught and tamed, undergoes so little 

 training in the field that it loses its natural dash, and is 

 often left behind by the antelope. It becomes so mild 



Fig. 4. — A restless bedfellow. 



that it is frequently allowed to curl itself under the same 

 blanket with its keeper. The keeper, when his bedfellow 

 is restless, " lazily stretches out an arm from his end of 

 the cot, and dangles a tassel over the animal's head, 

 which seems to soothe him." In the early morning Mr. 

 Kipling has seen a cheetah " sitting up on his couch, a 

 red blanket half covering him, his tasselled red hood 

 pushed awry, looking exactly like an elderly gentleman 

 in a nightcap, as he yawned with the irresolute air of one 

 who is in doubt whether he will rise or turn in for yet 

 another nap." This is mentioned as an instance of the 

 curious intimacy that exists in India between animals 

 and those who have charge of them. 



Of the remaining chapters we can only say that all of 

 them embody the results of a close study of the animal 

 world and of the Hindu character. We may note as of 

 especial interest the three concluding chapters, on animals 

 in Indian art, on beast fights, and on animals and the 

 supernatural. 



ON AN OPTICAL PROOF OF THE EXISTENCE 

 OF SUSPENDED MATTER IN FLAMES > 



■n\EAR PROFESSOR TAIT,— I write to put on paper 

 -'-^ an account of the observation I mentioned to you 

 to-night, in case you should think it worth communicat- 

 ing to the Royal Society of Edinburgh. 



In the course of last summer I was led, in connection 

 with some questions about lighthouses, to pass a beam 



' Read before the Royal Society of Edinburgh on June 15, 1891. Re- 

 printed from the Proceedings of the Society. 



NO. I 154, VOL. 45] 



of sunlight, condensed by a lens, through the flame of a 

 candle. I noticed that where the cone of rays cut the 

 luminous envelope there were two patches of light brighter 

 than the general flame, which were evidently due to sun- 

 light scattered by matter in the envelope which was in a 

 state of suspension. The patches corresponded in area 

 to the intersection of the double cone by the envelope, 

 and their thickness was, I may say, insensibly small. 

 Within the envelope, as well as outside, there was none 

 of this scattering. The patches were made more con- 

 spicuous by viewing the whole through a cell with an 

 ammoniacal solution of a salt of copper, or through a 

 blue glass coloured by cobalt. In the former case the 

 light from the flame was more weakened than the scattered 

 light, which was richer in rays of high refrangibiUty ; in 

 the latter case the patches were distinguished by a 

 difference of colour, the patches being blue, while the 

 flame (with a suitable thickness of blue glass) was purplish. 

 The light of the patches exhibited the polarization of 

 light scattered by fine particles— that is to say, 

 when viewed in a direction perpendicular to the 

 incident light it was polarized in a plane passing 

 through the beam and the line of sight. 



When the beam was passed through the 

 blue base of the flame there was no scattered 

 light. A luminous gas flame showed the patches 

 indicating scattered light like the flame of a 

 candle, but less copiously. They were not seen 

 in a Bunsen flame or in the flame of alcohol, 

 but were well seen in the luminous flame of 

 ether. When a glass jar was inverted over 

 burning ether, the blue part, which does not 

 show scattered light, extended higher, till, just 

 before the flame went out, the luminous part 

 disappeared altogether. A Bunsen flame, fed 

 with chloride of sodium, did not show the 

 phenomenon, though the flame was fairly 

 luminous. 



The phenomenon shows very prettily the 

 separation of carbon (associated, it may be, 

 with some hydrogen) in the flame, and at 

 the same time the extreme thinness of the layer 

 which this forms. It shows, too, the mode of 

 separation of the carbon— namely, that it is due to the 

 action of heat on the volatile hydrocarbon or vapour of 

 ether, as the case may be. At the base, where there is a 

 plentiful supply of oxygen, the molecules are burned at 

 once. Higher up the heated products of combustion have 

 time to decompose the combustible vapour before it gets 

 oxygen enough to burn it. In the ether just going out, 

 for want of fresh air, the previous decomposition does 

 not take place, probably because the heat arising from 

 the combustion is divided between a large quantity of 

 inert gas (nitrogen and products of combustion) and the 

 combustible vapour, so that the portion which goes to 

 the latter is not sufficient to decompose it prior to com- 

 bustion. 



In the Bunsen flame fed with chloride of sodium, the 

 absence of scattered light tallies with the testimony of 

 the prism, that the sodium is in the state of vapour, though 

 I would not insist on this proof, as it is possible that the 

 test of scattering sunlight is not sufficiently delicate to 

 show the presence of so small a quantity of matter in a 

 solid or liquid state. — Yours sincerely, 



G. C. Stokes. 



P.S. — I fancy the thinness of the stratum of glowing 

 carbon is due to its being attacked on both sides — on the 

 outside by oxygen, on the inside by carbonic acid, which 

 with the glowing carbon would form carbonic oxide. 



[When the above was written, I was not acquainted with 

 the previous paper by Mr. Burch, published in vol. xxxi. 

 of Nature (p. 272), nor did any of the scientific friends to 

 whom I had mentioned the observation seem to be aware 



