April 



1882.] 



KNOWLEDGE 



501 



Ifttns to tl)t eiJitor. 



{The Editor does not hold him*elf rerponzibU for fhfopiniotig of his eorrefponden/t. 

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 ecmmunir.itioni thould be at ahort oji potrible, consistently icith /ull ajid clear state- 

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All Editorial com munic alio ns should be addrested to the Editor o/ K>-owlbdgB; 

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All Letters or Queriet to the Editor tehirh require attention in the current is»ue of 

 EmowlbDGB, thould reach the Publishing OJice notlaterthan the Saturday preceding 

 the day of publication* ^^^^^ 



(I.) Letters to have A chance of appearing muBt be concise; they must be drawn 

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(ID Queries and replies should be eren more concise than letters ; and dra^m 

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(in.) Letters, quenes, and replies which (either because toolonff, or unsuitable, 

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ac.tioAledged i 



I only is to be contemned and despi«ed who is not in a 



here anything more adverse to accuracy 



*'In knowledge, that 



itate of transition 



than fliity of opinion." — Faradu 



'* There is no harm in making a mistake, but great harm in making none. Show 

 Be a man who makes no mistakes, and I will show jou a man who has done 

 nothing." — lA^hiu. 



" God's Orthodoxy is Truth."— CAarfw Kingaley. 



®\ix CoiTrsipontirnre Columns. 



ELECTRIC TELEGRAPH. 



[370] — It is pleasing to learn (letter 367, p. 179) that Sommer- 

 iiij's telegraphic apparatus is still in existence, but it must not be 

 forgotten that the idea of the electric transmission of intelligence 

 was not a novel one in Sommering's day. It is to Charles 

 SItirshall, a Scotsman, that we owe the invention of the electric 

 telegraph. He, in 1753, suggested that by erecting a series of 

 wii-es, one for each letter of the alphabet, and attaching to the 

 ^nd of each wire a ball, near which was suspended a piece of 

 paper free to move towards the ball, and inscribed with a letter of 

 the alphabet, and sending a charge of electricity through first one 

 wire and then another, the pieces of paper at the other ends might 

 be caused to move, and so to indicate the letters of the message 

 which it was desired to transmit. In 1774 Marshall's scheme was 

 realised by Le Suge of Geneva. Alfred W. Sow.ikd. 



GHOSTS. 

 [371] — The following details regarding the " War Office Ghost " 



may be of interest to T. D. In September, 1857. Captain G 



W , of the fith Dragoon Gnarfls, left England to join his 



ri-„'iment in India, leaving his wife at Cambridge. On the night 

 between the IJth and 15th Xovomber, 1857. she dreamed that she 

 saw her husband looking very ill, and she thereupon awoke, much 

 agitated. When she looked up she saw the same figure standing 

 by her bedside. He appeared in uniform, and seemed to be in great 



pain. Mrs. W at first thought that she must be still asleep, 



but, by rubbing her eyes, and by listening to the breathing of a 

 child beside iier, she became convinced that what she had seen was 

 no dream. In December, 1S57, a telegram from the seat of war 



appeared in the morning papers stating that Captain W had 



been killed before Lucknow on the fifteenth of November. This 

 date was further confirmed by the War Office certificate, which was 



obtained by the family solicitor. Mrs. W , however, maintained 



that Icr husband had died on the/ciurfeenf7i,and not on the fifteenth 

 as stated. While the solicitor's mind remained in uncertainty 

 regarding the real date of the death, a curious incident joecurred 



which seemed to confirm Mrs. W 'a opinion. The solicitor 



mentioned the case to a lady friend, who all her life had had per- 

 ception of apparitions. She immediately, turning to her husband, 



said, " That must have been the same apparition that I saw on the 

 evening we were speaking about India." The receipt for an account 

 paid on the same day enabled them to fix on the/ouWcenf/i as the 

 date. The solicitor was so much impressed by this that ho applied 

 to the War Office to find out whether there had not been some 

 mistake about the date. The officials stated that there could be no 

 mistake, as the death was referred to in two despatches from Sir 

 Colin Campbell, anil in both the date was given as the fifteenth. In 

 March, 185S, a letter arrived from a brother officer, giving an 



account of Captain W 's death. This officer, who had been 



riding beside Captain W when he was killed, stated that the 



death occurred on the fourteenth of November. Finally, about a 

 year after the death, the War Office altered the date to the 

 .fourteenth. Joiix Gouuox. 



MOON CRATERS. 



[372] — A propos of the notice at p. 439 of imitations of moon 

 craters, I was greatly struck only a few days since by the very 

 close resemblance to such craters in the impression produced on a 

 smooth surface of sand by a drop of water falling on it from a 

 height of about five or si.t feet. This is what happened in a green- 

 house on the moisture of condensation dropping into a pot sown 

 with seed and thickly covered with sand. 



Perhaps, as a small contribution to Kxowledge. this observation 

 may be acceptable. J. Power Hicks. 



COLOURS AT NIGHT. 



[373] — Can you tell me what is the explanation of the fact that 

 if a strip of cloth coloured either white, black, or blue be hungnp 

 on a pitch-dark night in a place where no lights are visible, and 

 against the sky as a background, it becomes swallowed up, as it 

 were, in the darkness, and is invisible ; but that if its colour be red, 

 it stands out as a dark patch on the black sky ? I have frequently 

 observed this to be the case, so that I am sure of my fact. 



Winter. 



GOLDEN SANDS. 



[371] — On the Western coast of India there is a river. To the 

 north of its mouth on the sea beach, during the south-west mon- 

 soon, appear many patches of black sand (grains of magnetic iron 

 ore). These patches average five or six square yards area, and are 

 about half-an-inch thick, and lie on the surface of the ordinary 

 yellow sand of the beach. The gold-washing natives carefnllj- 

 scrape off this black sand, during the rains, as fast as it appears, 

 and make heaps of it on the higher beach beyond the reach of the 

 sea at high tides. When the rains are over they wash these heaps 

 for gold, nsing first a small wooden cradle and then a shallow 

 gun-metal dish, such as is commonly used by natives for their rice, 

 and called a " Kinny." When the black sand is almost all washed 

 awav they use quicksilver, make an amalgam, squeeze the excess 

 of mercury out through a piece of washleather, and get rid of the 

 rest bv heat, leaving from two to six annas (threepence to eight- 

 pence) worth of gold for their day's trouble. My trouble is not how 

 they get the gold from the sand — that is easy enough, I have done 

 it myself a hundred times — but how did the gold find its way down 

 the river and on to the surface of the beach ? and why always in 

 company of the black sand ? 



Not one particle of gold is ever found in the yellow sand. There 

 is no adhesion or attraction between the black sand and the gold, 

 for the latter is as easily washed from the former as from yellow- 

 sand when mixed for experiment. I have tried it often. Why did 

 not the gold-dust find its way to the bottom of the river, as it did 

 at once to the bottom of the pan ? That is a Puzzler. 



JUPITER IN CASSIOPEIA. 

 [375] — With reference to your editorial remark respecting my com- 

 munication on "Jupiter in Cassiopeia" (correspondence column, 

 p. 478), I beg to say the context of the refreshing passage in 

 Schiller's " Wallenste'in," naturally suggests the interpretation I 

 put on the words of the poet, and every German reader who knows 

 the force of dnhin and has, besides, even an elementary knowledge 

 of astronomy only, would at once understand it to mean " yonder. 

 If Schiller had wished to make Wallenstein say, " that he saw 

 Jupiter t')! Cassiopeia," he would certainly have used darin, or some 

 similar expression. May I add that few poets have so carefully and 

 accurately worked out the details of their productions as Schiller 

 has done. In his brilliant tragedy of " Wallenstein," he has shown 

 that he had fully mastered the " subject of astrology," and it is 

 quite natural that he should have at the same time occupied himself 

 with the science of astronomy, if he had not done so before. 



C. A. BncHHEiM, Ph. D. 



