184.8.J 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



189 



LOCOMOTIVE CARRIAGE WHEELS. 



Edward Evans, of the Haigh Foundry Company, has obtained a 



patent for "cec/rn'it Improvements in the mode nf coiifitructijig iron 

 wheels."— Granted October 28, 181-7 ; Enrolled April 28, 18i8. 



This invention consists in a mode of securing tlie tyre or hoop of 

 the wheel to the spokes or inner rim, without the use of bolts or 

 rivets. The patentee effects this object by using a dovetail groove 

 in the tyre, and a dovetail projection on the rim, which is a method 

 that has been previously adopted, therefore he makes no claim to 

 that; but tlie peculiarity of his invention consists in making the 

 groove larger than the projections, and filling the interstices with 

 melted zinc. In the words of tlie specification, the patentee 

 claims " the maiuifacture of wheels in wliich tlie dovetail groove 

 in the tyre is wider at its narrowest part than tlie dovetail ])ro- 

 jeetion on the spokes or the inner rim of the wheel is at its widest 

 part, and the filling the spaces left when the tyre is shrunk on with 

 melted metal or other hard substance. The accompanying section 



of the tyre and its junction with the wheel, will sufficiently show 

 the form of the grooves and projections. The dark portions re- 

 present the zinc or other easily-fusible metal with which the spaces 

 are filled. 



Locomotive En-gines. — GEORfjE IIeaton-, Birmingham, engineer, 

 has obtained a patent for '•^ Improcements in- locomotive enr/inex." 

 Granted November 9, 1847 ; Enrolled May 9, 184.8.— The object of 

 this invention is to prevent the oscillation of locomotive engines on 

 railways ; and the patentee endeavours to effect tliis by the appli- 

 cation of counter-balance weights, moving in an opposite direction 

 to the pistons of the cylinders. The mode of applying these counter- 

 balance weights is as follows : — On each end' of the axle of the 

 driving-wheels is placed a crank, to which is united a connecting- 

 rod attached at the other end to the counter-balance weight, wliicli 

 is suspended between two rods, so as to swing readily to and fro, 

 or it is held between fixed guide-rods, to admit of its sliding easily. 

 The counter-balance weights should always move in the direction 

 opposed to that of the pistons, and should be as heavy as the com- 

 bined weight of the pistons and the working-gear. 



Compound Beams or Girders. — Henby Fielder, Maida-vale, 

 has obtained a patent for " Itnproi^ements in iron heamx or girders." 

 Granted November 9, 1847; Enrolled May 9, 1848.— The patentee 

 constructs his beams partly of malleable, and partly of cast-iron. 

 The lower or tension flanges are made wholly or partly of malleable 

 iron, while the centre ribs and upper or crushing flanges are wholly 

 or partly of cast-iron, according to the duties they have to perform. 

 The lower flange may be made of, or strengthened by the addition 

 of malleable iron, and the centre rib and upper flange remain of cast- 

 iron ; or, the upper and lower flanges may be of malleable iron, 

 united to the centre cast-iron rib, and further strengthened, when 

 exposed to vibration, by angle-iron ; or, the perpendicular ribs 

 may also be composed of malleable iron, when exposed to violent 

 concussions. The malleable iron is united to the cast-iron by hot 

 rivetting, and, in all cases, in such proportion that it shall be able 

 to support, alone, the estimated weight to which the whole girder 

 may be subjected. The invention consists secondly, in the appli- 

 cation of the preceding principle of construction to the strengthen- 

 long or repairing of existing beams or girders, with such variation 

 of detail as the particular case may suggest ; and thirdly, to the 

 construction of beams or girders composed entirely of malleable 

 iron, in which case the flanges are united to the centre rib by 

 angle-iron, the coupling-joints headed, and the whole are fastened 

 together by hot rivetting. 



ELECTRICITY OF .MINERAL VEINS. 

 Mr. Robert Hvnt (keeper of mining records at the Museum of 

 Economic Geology) lately delivered a lecture on the " Electricity of 

 Mineral Veins" at the Royal Institution, Albemarle-street. 



The lecturer commenced by remarking, that the class of pheno» 

 mena which would form the subject of consideration that evening, 

 although of the highest interest, had not yet received so great an 

 amount of experimental examination as their importance required; 

 and, as their curious nature was, consecpiently, not generally 

 known, he trusted that, having spent many days'and nights in the 

 mines of C^ornwall, in tliis investigation,' he' should be able to 

 interest his audience by a narrative of the facts now known as 

 well as some of a novel character. 



As a preliminary of absolute necessity, Mr. Hunt explained the 

 nature of a mineral lode by the aid of a beautiful isometrical 

 drawing of the lead district of Nentsford. A lode was, in fact a 

 fissure, formed by some disturbance of the earth, and filled with 

 mineral dejiosits. Three theories prevailed as to the origin of 

 mineral lodes ; in the first place, they were supposed to be con- 

 temporaneous with the rocks themselves ; secondly, it was con- 

 ceived, that fissures were filled by the sublimation of matter from 

 great depths in tlie earth ; and, lastly, that substances were preci- 

 pitated from sidution in water, h liich flowed through those great 

 rents in the eartli. A mineral lode was not to be regarded as being 

 entirely composed of metallic substances ; on the contrary, they 

 were most fre(iuently found containing a large portion of earthy 

 matter, amongst which the metallic ore was disseminated. Among 

 the indications which appeared to support the theory of electric^ 

 action in tliese formations, was to be regarded tlie regular dispo- 

 sition of these substances on either side of the lode. The elec- 

 trical theory might be exjilained in a few words. Ampere sup- 

 posed that currents of electricity traversed tlie earth from east to 

 west, and these currents were thought to influence the chemicid 

 changes which had gone on within the fissure during the formation 

 of the lode, and determine the order of arrangement. The most 

 striking conditions which appeared favourable to such a view were, 

 that metals of various kinds were associated with peculiar cb.sses 

 of rocks — tin and copper being associated, in a remarkable manner, 

 with the primary rocks ; whilst lead was found more abundantly 

 in the limestone formations. These rules, altliough genera], were 

 not constant — many striking exceptions miglit be named. In the 

 remarkable mining county of Cornwall the rocks were granite, 

 killas or clay-slate, greenstone, and elvan. The mineral lodes 

 were always most abundant near the junction of the slate and 

 granite rocks ; they were generally found in a direction nearly 

 from north-east to south-west ; and where they were contrary to 

 this, or nearly in the line of the magnetic meridian, there was 

 almost invariably a great difference in the character of mineral 

 substances contained in the lode. This was shown by reference to 

 a very large map of C^ornwall, upon which the lodes of lead and 

 copper were accurately marked. Again, a very remarkable 

 parallelism was observed in most districts between the directions 

 of the lodes, and the veins of granite prophyry (elvan) which oc- 

 curred in their vicinity ; and this fact had been brought in support 

 of the theory, which refers mineral formations to the action of 

 subterranean heat. 



The various questions which arose out of the phenomena of 

 mineral veins, and their including rocks, had been most ably 

 treated of by Sir Henry De la Beclie, Mr. Joseph Carne, Mr. R. 

 W. Fox, Mr. John Taylor, Mr. Hopkins, and others; he would 

 not, therefore, dwell on that part of the subject. 



Mr. Hunt next considered, whether any of the conditions known 

 to belong to the rock formations of a mining district were suflS- 

 cient to produce electrical phenomena. It had been ascertained 

 that granite was always colder than slate — a difference of 20° or 

 30° was always detected at all depths. This difference might pos- 

 sibly give rise to weak thermo-electric currents ; but, in the ex- 

 periments he had made to ascertain this point, no such currents 

 had been detected. It was also well known that a constantly in- 

 creasing temperature was discovered as we descended into the 

 earth. By this means, it was evident that any given portion would 

 represent a bar unequally heated. The following table of tem- 

 peratures, obtained in the rock and lode, exhibited the variations 

 of temperature in the deep mine of Tresavean : — 



At sea level.. .. In granite.. .. 57° F. 

 Atl/Ofms.. .. Lode in slate .. 77° F. 



Atl96fiiis.. .. Doingranlte .. 83° F. 



At208fras.. .. Do in granite .. 85° FJ 



At310fms.. .. In granite .. 94° F. 



According to the generally received views of thermo-electric 



