76 



KNOWLEDGE. 



[April 1, 1896. 



be of practical value in surgery. Prof. Salxioni's results 

 are, however, a very striking corollary ol Prof. Ivontgen's 

 discovery. In repeating Prof. Salvioni's experiments, I 

 first tried his method of saturating blotting paper with a 

 solution of the powder, but I think my plan gives more 

 light. Parinm platino cyanide costs, unfortunately, eight 

 shillings a drachm, so the experiment should be cautiously 

 made. 



As bearing on the limitations of electrography with 

 regard to surgery, I may mention that an attempt to get 

 at the inside of an incubating egg failed. Only the graining 

 of the shell appeared on the negative, because an egg is 

 completely surrounded with a substance which, like bone, 

 is opaque to the influence. If this be so, what becomes of 

 the marvellous tales about the photographs of the inside of 

 the living skull? If the head be electrographed, what can 

 be obtained but a mass of bone with no definition ? For 

 the brain is surrounded by bone, except at the holes for 

 the optic nerve. 



As far as electrography has gone, its uses to the surgeon 

 are little or none — at least that seems to be the opinion of 

 the medical men with whom I have talked on the subject ; 

 but there is one way in which, even at this early stage, it 

 is of practical use. A girl had a diseased fiuger-bone on 

 which she did not like an operation to be performed. The 

 electrograph of her hand, though showing little or nothing 

 to the surgeon of which he was not before aware, at once 

 convinced the patient, and the operation will shortly take 

 place. Electrography should also save probing in wounds 

 of the hand or foot, and, probably, at no very distant date, 

 in any part of a limb. I think this is all that can be 

 claimed for it at present, but even that seems a good deal 

 for a few weeks' work. 



]Many people have curious notions about electrography. 

 A parent wrote to ask if the child's diseased bone could be 

 photographed ; there would be no difficulty, as the child 

 was very good and the room to which it was confined had 

 a south aspect. An old lady wished to have her head 

 photographed, for she had lately become deaf — she was not 

 always so — and she thought it would be a good thing to 

 know what caused her deafness ; she had tried " other 

 remedies " in vain. A student, hearing me describe my 

 methods, interrupted with " Oh ! we know all that ; we 

 have done all these experiments here." I asked to see the 

 results. " Well " — in a tone which rebuked the irrelevancy 

 of the question — " there were no results." 



The enlargement, due to the distance of the hand from 

 the plate in the earlier experiments, is, I am told by a 

 psychic investigator, caused by the " Odic Nimbus." Call 

 a spade a spade, if you will ; but remember that a shadow 

 is an odic nimbus. It is a much nicer name. 



In case any reader wishes to repeat these experiments 

 but is deterred by not knowing the cost, I may say that a 

 ten-iuch spark coil costs £4(,>, a hand dynamo about £15, 

 and a Crookes tube about 25s. It is not suggested that 

 my apparatus is the best possible, but merely that good 

 results have been obtained by its means. Where there is 

 some means of re-charging them, accumulators are better 

 than a dynamo, because they are less trouble and the 

 current is more even. 



Note. — Since writing the above, I have succeeded, with 

 an improved tube, in electrographing my own hand in one 

 minute. The bones show right down to the wrist, and the 

 commencement of the ulna and radius is clearly differen- 

 tiated. The plate was so much over-exposed that I believe 

 half a minute would be quite enough. No Tesla transformer, 

 nor any other apparatus than that mentioned above, was 

 used. 



NOVEL EXPERIENCE WITH RONTGEN RAYS. 



WuiLK carrying out experiments with Eontgen rays we 

 have obtained results which we consider worth further 

 careful investigation. 



On exposing a plate contained in an ordinary card- 

 board plate-box with the object of obtaining a shadow- 

 graph of keys, coins, etc., on the top, we failed to obtain 

 the usual image ; on exposing another plate in the same 

 box after a trifling alteration of apparatus, but with an 

 entirely different series of objects, we obtained on develop- 

 ment a well-defined image of the objects first exposed. 

 Struck with this phenomenon, we made another exposure 

 in the same box with a plate from a fresh packet, and, on 

 developing, obtained a good image of the objects placed 

 for the second exposure. We have repeatedly obtained 

 these remarkable results under the following varied con- 

 ditions : — 



Exposure made and no result ; box left for two days ; fresh 

 exposure made with entirely different objects, and resulting 

 negative clearly defined objects placed in the box two days 

 before. 



I'jxposure made and box exposed to strong daylight, to 

 ascertain if sunlight would discharge the latent image, 

 but with no effect. After an interval of eight days, box was 

 again subjected to X rays, and a negative obtained of 

 objects exposed eight days previously. 



This is at present entirely inexplicable, and as we only 

 seem to get these retained or latent impressions with one 

 box we have not yet subjected the cardboard of which it 

 is composed to more than superficial examination. It is 

 our intention to endeavour to obtain more boxes of this 

 particular batch, and if with these we can confirm our 

 present results, we hope to elaborate a theory which will 

 account for what we can only now term ' ' the storage and 

 transformation of images formed by X rays in certain 

 undetermined varieties of cardboard." 



We may add that the apparatus used was a two and a 

 half inch spark coil, operated by a chromic acid battery, 

 using sometimes special Crookes tubes and sometimes a 

 small incandescent lamp with broken filament, for pro- 

 ducing the X rays. 



Leon J. Atkinson. 

 Arthur H. Pook. 



March 18th, 1896. E. P. Williams. 



ALUMINIUM: ITS HISTORY, MANUFACTURE 

 AND FUTURE.-I. 



By Samuel Eideal, D.Sc.Lond., F.I.C. 



VEEY few chemical discoveries of the present 

 century have evoked so much interest as that 

 of the introduction of aluminium. At the Paris 

 ''Exhibition of 1855 it was exhibited for the first 

 time in public, and was regarded as one of the 

 principal novelties of that year. The new metal was 

 shown as a bar, bearing the very sensational inscription, 

 " Silver from Clay, " and was regarded even at that date as 

 the metal of the future, with boundless possibilities of 

 usefulness. The non-scientific press devoted long articles 

 to its description, and pointed out that a metal with 

 apparently all the qualities of the noble metals, and 

 excelling them in having a remarkably low specific 

 gravity and in its general stability, had been produced 

 from one of the most abundant materials on the surface of 

 the earth ; and the inventors of the process were hailed as 

 benefactors to humanity and honoured as accomplishing 

 one of the greatest achievements of science. The first 



