206 



THE CIVIL ENGINEER AND ARCHITECFS JOURNAL. 



[JULT, 



MAGNETIC EXPERIMENTS ON METALS, ALLOYS. AND METALLIC 



SALTS. 



A paper on tliis sutiji-rt was lately read hy Mr. William Sturgeon, at the 

 Manchealer Literary md Philosophical Society. After liaving talicn a retro- 

 .pectivr view of th.- lahimrs of ,illwr .xp'-iiincntali-ts in this liepartment of 

 magnetics, llie author proceedeil to ilescrihe a novel apparalos liy means of 

 which liis own experiments liad heen made. It eoiisisls principally of a 

 po^^■erf^l magnet and a liglit wooden lever, delicately suspended hy a few 

 silken tihres, the whide lieing enclosed in a glass rase. By means of tins 

 apparatus, Mr. S. lias found that gold, silver, copper, platinum, antmiony, 

 bismuth, lead, till, and some other metals, when pure, art peifcclly neutral 

 to the action of the magnet, but that when some of tliem are comhined they 

 become maKiietic in an eminent degree. Some of his eacliest experiments, 

 especially those on hrass, many specimens of which he found to he magnetic, 

 led him to suppose tliat their magnetic actions were due to small portions of 

 iron which they contained ; for in some of the metals of commerce on which 

 he experimented, iron was ahsolutelv present. In a mass of hismuth, for in- 

 stance, iron was found in consideralile proportions. Mr. ,S. has discovered 

 that all our silver coinaue is magnetic, hut in difTirent degrees, according to 

 the dates of its production. Domestic articles of silver, as spoons, &c., are 

 itill more magnetic than silver coins. Gold coins are also magnetic, hut not 

 80 highly as silver ones. The gold of articles of jewellery is more magnetic 

 than gold coins. Mr. S. was still of opinion that these alloys might possihly 

 contain iron, and their magnetism be therefore dependi-nt on that metal, al- 

 though he had met with some facts which he could not reconcile to that 

 view. Having found much more magnetism in an old half-crown piece of 

 William and Mary than in any other coin, and the histniical report heing 

 that the silver coinage of that period was in a very hase state, he supposed it 

 possible that the high magnetic action of the old half-crown might he due to 

 the extra proportion of copper, which led him to (orni an alloy of pure silver 

 and pure copper, in which the latter metal formed ahout one-sixth part of 

 the whole ; and what is very remarkahle, this alloy was more highly magna- 

 tic than any siUer atticle he had previimsly examined. The copper and silver 

 of this alloy had previously been ascertained to ne non-magnetic ; they were 

 melted in an earthen crucible, and no inm entered the alloy. This fact, and 

 »ome others which he subsequently discovered, shook the opinion Mr. Stur. 

 geon had first formed respecting tiie pre ence of iron in brass, and the other 

 alloys which showed magnetic action. Cavallo had discovered the magne- 

 tism' of hrass, and showed that hammered hrass was never more magnetic 

 than when unhammered, which facts corresponded to Mr. Sturgeon's own 

 observations, liul the most capital discovery bad yet to he made. Mr. S. 

 formed an alloy of iron and zinc in equal parts, and, to his surprise, found 

 that this alloy was almost neutral to tin- magnet; so much so, that it would 

 not move a magnetic needle at half an inch from the pole. In another alloy 

 of those metals, the iron being about one-eighth of the zinc, magnetism was 

 quite extinct. These novel facts naturally led to the inference, that as zinc 

 is an essential constituent of brass, the magnetism of that allov could not be 

 owing to its containing iron ; and subsequent experiments, both magnetic 

 and chemical, have shown that this is the fact. Antimony has long been 

 known to deteriorate the magnetism of iron, but Mr. S. has ascertained that 

 its neutralising powers are much inferior to those of zinc. An alloy of anti- 

 mony and iron, in which the latter metal was less than a twentieth part, 

 still showed magnetic action, though in a slight degree. Mr. S. had also dis- 

 covered that nickel loses all its magnetic powers when alloyed with about 

 ten times its weight of zinc. Antimony also counteracts the magnetism of 

 nickel, hut not so powerfully as zinc. German silver, which conlains a large 

 proportion of nickel, is slightly magnetic; but in the inferior kinds of this 

 alloy, where nickel is less abundant, no magnetism is perceptible. The neu- 

 tralising metal in these cases is zinc. 



The salts of iron which have been examined are mostly magnetic ; but 

 what is remarkable, their magnetism hears no proportion to the proportions 

 of iron thev contain. In conforming bis theoretical views to the fads thus 

 developed, 'Mr. i. now considers all bodies to be more or less magnitie, and 

 classes them into two grand divisions— those that are palpably magnetic, and 

 those that are hut obscurely magnetic. The former class he calls sapho- 

 magnetics, and the latter asapho maynelics. 



Sapho magnetics are again divided into mono-magnetics and suno-magnetics, 

 accordingly as tluy consist of indiviriu.al or compound bodies respectively. 

 Those bodies which counteract the magnetism of others, Mr. S. calls kaialo- 

 magnetics, because many of them, if not all, have the power of completely 

 neutralising even the highest powers of mono-magnetic bodies. 



The mono magnetics at present known are iron and nickel, and perhaps 

 cobalt. In the class suno magnetics. .Mr. S. places alloys of silver and cop- 

 per, gold and copper, and zinc and copper, under the expectation that many 

 more will soon be added to their number. The katalu-magnelics are very 

 numerous, being all those that deteriorate the magnetism of other bodies. 

 Amongst the metallic iatalo magnetics, Mr. S. has found zinc, antimony, tin, 

 and lead. Giber ialalo magnetics are sulphur, oxygen, chlorine, cyanogen, 

 and the generality of those bodies which combine with metals. 



RAILWAY STATISTICS. 



The annual return of the Board of Trade, recemly published, coutaiu* 

 some very vnludble informatiou on the subject ot rail»a> suii.lics. 'i ho 

 following lufonoHtiou is taken in a condensed form Irum that itluru:- 



The toial number of passengers, as giveu lu the returns lor the year 

 ending 30tb June, 1844, and for the year ending 3Uth Juue, ls4o— 



1844. 1845. 



1st class .... 4,874,;i32i 5,474,103 



2ndcla=8. . . - l2,2S...(ii.O 14,3-.i..,b2.5 



3rd class .... 8,5b3.li85i lJ,l.io,b;iU 

 Mixed . . . • 2,Oli'J4>Jo4 8 5,445i 



27,703,002^ 33,7yi,-,!531 



The rate of increase of travelling in each class is— 



Ist class 12 per cent. 



2iid class " percent. 



3rd cla=s 15 upwards of . . • 50 per cent. 



The amount received for each class is as follows :— 



1843 4. 1844 5. 



1st class . . .£1,432 088 £l,.il0,8ti5 



2nd class . . ■ 1,3(5 071) l,oU6,.l5 



3rd class - - • 4S3,u09 twi,-JU3 



Mixed . - • 147.ftob 2uy,.)18 



Total . . £3,43y,2'Jl £3,070,341 



The increase of n turns on the year 1844 5 w,i3, thtreiore, upwards of 

 half a m.llioii on tasscugcr traUic alone. Ou gioas receipts from all 

 sources it stood thus : — 



1843-4 £.-.,071.074 



la44-4 WMUi 



Increase . . 1,135,040 



The rale of fares on the lines included in the above returns, and the re- 

 ductions in liie two years, staud thus al the eud of tne year 1845 :— 



Ex- 



press. C 



d. 



300 ; 



m 2-88 : 



2-44 



■ester '■ 



(1. ; 



J . 3-4G ; 



2 97 ; 



2-87 

 igbam 2i7 



ton 3*23 : 



245 



nd 

 Catllt', Sheeji, Ifc.—TUe total number of cattle conveyed in the year 

 1844-5 IS nearly two millions. The gloss auiouuis received range as lot- 

 lows : — 



London and Kirminghani 



Oil eat Western 



Midland, and Bristol and Birmingham 



Kastern Counties 



South Western 



Manchester and Leeds 



York and North iMiiIlaud 



Oreat North of England 

 Horses. — The number conveyed is as follows : 



Bristol and Birminghaiu 



Chester and Birkenhead 



Eastern Counties 



Noriheni and Eastern . 



Grand Junction 



Manchester and Birmiiighaui . 



Great Nortii of England 



Great Western 



London and Birmingham 



London and Souih Western 



London and South Eastern 



Londou and Urightou 



Manchester and Leeds 



£50,000 

 17,000 

 9,000 

 5,300 

 4,0u0 

 4.00U 

 3,200 

 3,200 



2,879 



664 



2,160 



2.706 



4,207 



785 



2,709 



10.504 



10,749 



5,570 



2,714 



4.303 



1,409 



