December i i, 1902J 



NA TURE 



m 



Dunedin, who are unable to discover anything out of the 

 ordinary. The chief asks for silence and a hush falls on 

 the scene. The assembled natives break into loud cries, 

 and along a track in the jungle-like growth can be seen 

 a party of ten Fijians fantastically dressed. 



" Without hesitation or haste, they step on to the 

 stones and walk round the pit, taking some ten to 

 fifteen seconds to complete the circuit. They step off 

 quickly, and in a moment great masses of green leaves 

 are thrown on to the centre. The fire-walkers rush back 

 and press down the leaves with their feet and hands. 

 The steam rising from the leaves envelops them in a 

 cloud. Baskets of native food are passed in, and more 

 green leaves are heaped over until a mound is made." 



Dr. Fulton states that the man Dr. Smith and he 

 examined before the fire-walking was of fine physique, 

 with a pulse a little over 90 and the hands and feet 

 cooler than the rest of the body. The feet were perfectly 

 clean and odourless, and no preparation could be de- 

 tected on them. The soles were yellowish-white, per- 

 fectly smooth and pliable, and like soft kid. The man 

 wore a sulu (petticoat) of dry hibiscus bark and canna 

 leaves, with small anklets of dry bracken. Each man as 

 he walked kept his eyes on the stones. One man was ex- 

 amined afterwards ; his pulse was about 120 ; the soles of 

 the feet seemed cool, if not cold, but on running the hand 

 up the leg, a most pronounced difference in temperature 

 was observable ; on the calf, it was like that of a man in a 

 high fever. None of his vegetable clothing was scorched, 

 not even the dry bracken anklets, and the short, black, 

 crisp hairs on the legs were not singed. Dr. Fulton 

 went to the edge of the pit immediately after the cere- 

 mony and stirred up some of the stones with his foot. 

 He stood for a second on one or two and found that they 

 did not brown his boots, though evidently they were too 

 hot to handle. He asked a native to get him one of the 

 stones, and the man coolly walked up and began to move 

 about the heated stones with his bare feet. This was not 

 one of the " fire-walking " men, but one of those who had 

 come from Suva. He raked out a piece of stone from 

 the heap, but it was too hot to hold in the hand. 



The explanation Dr. Fulton offers is as follows. The 

 arrangements for heating were peculiar ; if what was 

 required was merely a surface of red-hot stones to walk 

 upon, it would be easier to lay flat stones in the pit and to 

 maintain a huge fire on them. The stones took forty- 

 eight hours to get to their "proper" condition, and 

 the subsequent cooking of the food took two days 

 instead of an hour or so. The stones also were found to 

 cool very slowly. The same stones are never used 

 twice. They are gradually heated until split by the 

 expansion of the contained water, and are then carefully 

 arranged fractured side upwards. The stone that was 

 examined was an augite-andesite of ordinary type. Prof. 

 Park, of the Otago School of Mines, found that, taking the 

 thermal conductivity of copper as equal to 1000, that of 

 andesite is 667, that is, it is a very feeble conductor of 

 heat. In testing the radiation, iron being the standard 

 at 100, andesite is 48. Thus the fractured, or inside, 

 surface of the stone, owing to its slow conductivity, 

 does not receive nearly the amount of heat one would 

 expect, and, owing to the slow radiation of heat, the foot 

 is not burnt when coming into contact with the stone for 

 a second or less ; as a matter of fact, the sole of the foot 

 was at no time in contact with a hot stone for more than 

 half a second. The foot is naturally cold or artificially 

 cooled ; it is a well-known fact that one can bear with 

 cold feet for a long time (up to a minute in some in- 

 stances) heat from a fire which would be insupportable 

 for five seconds at ordinary foot temperature. 



A good deal has been written at various times on 

 walking on heated stones or glowing embers. It will be 

 in the knowledge of our readers that there was pub- 

 lished in Nature of August 22, 1901, an article on 



NO. 1728, VOL. 67] 



Tahitian fire-walking, by Prof. S. P. Langley, in which a 

 somewhat similar explanation was given. It is satis- 

 factory to find that these investigations by scientific 

 men agree, on the whole, with one another in principle, 

 and that a rational explanation is forthcoming for a 

 sensational performance which unskilled white observers 

 usually regard as mysterious or even as miraculous. 

 The walking on glowing embers, which is well known in 

 parts of India, as recently described in the Bulletin of 

 the Madras Government Museum (vol. iv. 1901, p. 55)> 

 probably has another solution. The fire-walking cere- 

 monies in India, Japan and elsewhere require to be care- 

 fully studied by trained observers. A. C. H. 



THE PRESENT STATE OF WIRELESS 

 TELEGRAPHY. 



IT is now eighteen months since we last attempted in 

 these columns to take a general survey of the 

 development of wireless telegraphy. In the history of a 

 science which has enlisted the services of so many skilled 

 experimentalists, each of whom has made rapid progress 

 along his own lines, eighteen months is a comparatively 

 long period ; as a result, we are compelled to-day to regard 

 the subject from a very different point of view. At that 

 time, there were practically only two systems — Mr. Mar- 

 coni's and Prof. Slaby's— which had advanced to such a 

 degree of perfection that they deserved special considera- 

 tion. To-day, it would hardly be too much to say that in 

 every civilised nation there are one or more inventors- 

 with a carefully worked-out and tested system ready for 

 general use. Particulars of these different systems have 

 been published from time to time and have been duly 

 referred to in Nature ; unfortunately, the information 

 published is not, as a rule, of the kind that one most 

 desires to obtain ; too often it is obviously " inspired,'* 

 and consists for the most part of insufficiently supported 

 claims to successful syntonisation, or to record making in 

 the way of long-distance transmission or rapid signalling, 

 information which is very acceptable to the daily papers, 

 which forget one day what they have published the day- 

 before, but of little use to those who are seriously inter, 

 ested in the subject. 



So far as can be judged, the various systems differ 

 chiefly in matters of detail, the design of circuits and 

 the special construction and arrangement of apparatus ; 

 improvements depending on the introduction of a 

 principle fundamentally new are few and far between. 

 We do not wish to underrate the value of these detailed 

 improvements ; they are, as we well know, often the talis- 

 mans converting failure into success, but their interest is 

 mainly for the specialist It is not our intention, therefore, 

 to enter into a detailed examination of the different 

 systems ; to do so would only involve us in a mass of 

 technicalities from which the reader would probably 

 " come out by that same door where in he went." Those 

 who wish for this information must be referred to the 

 technical Press or to the files in the Patent Office, where 

 they will probably find, as, for example, in the two hundred 

 odd claims in Mr. Fessenden's patents, all the particulars 

 they desire. We propose rather to treat the subject on a 

 broader basis, and to endeavour to form an estimate of 

 how far wireless telegraphy in its present state has fulfilled 

 the expectations that have been raised in the past or 

 justifies hopes that may now be entertained for a future of 

 wide utility. 



The first question that one feels inclined to ask is, At 

 what end are all these inventors aiming? Is it to devise 

 a system of wireless telegraphy to compete with the ordin- 

 ary telegraphic methods, or is it for what seems to us the 

 more useful purpose of creating a means of communication* 

 where none now exists, especially between ship and ship and 

 ship and shore ? It would seem that in some instances, as, 



