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Sl'RIXU CARRIAGE. 



Sl'l'.l 



736 



century In the early carriages of this kind the (traps were usually 

 attached to a framework of wood at each end of the vehicle, rising to a 

 considerable height above the axles. The antique four-wheeled 

 carriages of Europe used for state purposes are mostly constructed on 

 this plan ; and their great weight and slow movement prevent any 

 violent concussion. A serious disadvantage of this construction is the 

 great length of carriage that it renders necessary, and the cumbrous 

 character of the wooden framework which supports the braces. The 

 carriage must also be heavily loaded, in order to make the motion 

 tolerably comfortable, especially when the straps are suspended from 

 points not much higher than the bottom of the body. To remedy the 

 defect* of the primitive slung carriage, it was desirable to render the 

 pillars from which the straps were suspended somewhat elastic. This 

 could not be readily effected with wood, because the pillars were 

 necessarily short, and therefore stiff. Hence arose the use of elastic 

 steel supports, which have gradually assumed the form now well known 

 as C-springs. 



Straight springs of steel probably owe their origin to the straight 

 wooden springs occasionally used in light vehicles in this and other 

 countries. Used either singly or in combination, they afford sufficient 

 elasticity for many purposes, without raising the body to an incon- 

 venient degree, or interfering with its form ; since they may be placed 

 entirely beneath it, and require but little room for their play. AY//;, 

 tical springs have, in some degree, the same advantages; but they 

 require rather more depth than straight springs. 



Carriage-springs are usually formed of several thin plates of steel, of 

 various lengths, so laid and fastened together that the spring shall lit 

 thick in the centre, or at the end by which it is fixed, and thin, in- 

 consisting of only a single plate, at the end or ends where the greatest 

 play is required. The steel used is of coarse quality, and has little 

 carbon in its composition. It is fashioned by rolling-machinery to the 

 transverse dimensions required, which vary from one inch and a half 

 to three inches in width, by one-eighth of an inch to half an inch in 

 thickness. The plate forming the back of the spring is usually 

 thicker than the rest, on account of its being the longest, and having 

 its ends formed into bolt-eyes, to receive the bolts by which the body 

 is connected with it. With this exception, it is not usual to make any 

 difference in thickness in the several plates of a spring, notwithstanding 

 their different lengths. After the plates have been wrought into the 

 form required, they are hardened by heating in a hollow fire, and then 

 plunging into water. They are subsequently tempered by drawing 

 them again through the fire, until they become so hot that a stick 

 rubbed over the surface will be kindled to a blaze. Any accidental 

 warping acquired in these processes is removed by hammering, the 

 plates being slightly warm during the operation, to avoid the risk of 

 breakage. They are then finished by filing all the parts that will be 

 exposed to view when the spring is complete; and are finally put 

 together and secured by a square hoop of iron, which is shrunk on hot, 

 and by a rivet passing through the hoop and through all the plates. 



Coach-makers apply distinct names to a great many varieties of 

 springs ; but those which are most generally used may be briefly 

 enumerated. The straight spring, if single, is the iingle-elbot' 

 The double-elbow ipring is a straight spring, acting on both sides of the 

 fixed point. It is a kind of spring very extensively used in stage- 

 coaches, omnibuses, and light two-wheeled vehicles. Ellij>ti<- 

 are used single in some carriages, between the axle and the frame- 

 work ; the spring resting on the axle, and being connected with the 

 carriage by means of a curved bar of iron, called a dumb-inn, placed 

 over it like another spring. The spring is then called an vtder^pring. 

 Elliptic springs are often used in pairs, under the name of nut-cracker 

 tpringi, the two springs being hinged together at each end, so as to 

 form a long pointed ellipsis. In this way elliptical springs are much 

 used in Mich four-wheeled carriages as have no perches. C 

 consist of two thirds of a circle, lengthened out into a tangent ; the 

 tangent being laid horizontally, and bolted down to the framework of 

 the carriage. When these springs are used, the body is not, as in 

 most other cases, connected immediately with the springs, but is 

 suspended by leather straps, which pass round the back of the springs, 

 and arc fastened to the framework near to their base. Telcyraph- 

 tprivrji are combinations of straight springs in sets of four. Two are 

 placed longitudinally, resting cither immediately upon the axles, or 

 upon the lower framework of the carriage ; and two others, placed 

 transversely, are suspended from their ends by shackles. The body is 

 supported upon the centres of these transverse springs. Tllburi/- 

 tpringi arc another combination of straight springs. Two single-elbow 

 springs are attached to the hinder part of the body, and suspended by 

 leather braces from a transverse spring elevated on an iron standard at 

 the back of the framework. The front of the body is suspended from 

 the shafta by two single-elbow springs with short leather braces ; and 

 sometimes a pair of double-elbow springs are interposed betwei n i In- 

 shafts and the axle. Dennet-npringt are a combination of three straight 

 springs, two of them placed across the axle, and attached at their fore 

 ends to the shafts or the framing of the body, and the third placed 

 transversely, suspended by shackles from their hinder extremiti 

 fastened to the body at its centre. The bodies of private cabriolets 

 are usually hung ujmn C-i]irin;,, with small curved springs in front, 

 and double-elbow springs frequently added between the shafts and the 

 axle. The combination of springs used in under spring carriages is the 



most effective which has yet been discovered for producing the 

 minimum of concussion or motion to the passengers. The body of 

 such a vehicle is suspended by braces from C-springs ; and the : 

 work of the carriage to which the C-springs ore fastened, is sup; 

 upon under-springs, which intercept concussion from the uneveuness 

 of the road. 



( if these various springs, none but the C-springs with leather braces 

 allow universal motion to any important extent. In some carriages 

 loops of leather or caoutchouc have been used, instead of iron shackles, 

 for connecting straight springs, by which means the motion is rendered 

 pleasanter, and the rattling uoi.-e of the shackles is avoided. Another 

 >f ordinary springs is their want of adjustibility to the Wright 

 they have to carry. They must, of course, be made strong enough to 

 sustain the maximum weight they are intended to bear ; but, by being 

 so, they become too stiff to play easily under a light load. To meet 

 the deficiencies of the springs in common use, Mr. Bridges Adams con- 

 trived one on the principle of the bow, which will yield in any direction, 

 aud may be made capable of adjustment, by means of screws, to a light 

 or heavy load. This spring consists of a single plate of well-tempered 

 steel, forced into a curved form by the tension of a chord of prepared 

 hempen rope, or of a riband of iron or steel, and to which the axle is 

 attached. There are two bow-springs, a b and c <7, connects 1 with 

 other and with the same axle. These ore jointed together at b c, and 



attached to the body, of which the lower framing is shown at //, by 

 movable joints at a and d, which allow the springs to lengthen and 

 shorten in playing. The chord of each bow is in two parts of unequal 

 length, each of which is connected at one end with the bow, and at 

 the other with the axle at e ; so that the chord of the bow, o b; takes 

 the direction a e b. and that of the bow, e d, the direction c e d. Among 

 the advantages claimed for them are their lightness and extreme 

 elasticity, arising from the superior quality of the steel, and the 

 absence of the friction which attends the action of the common 

 laminated springs. 



All the springs that have been alluded to in this article are bcariny- 

 f/irint/s, for supporting the weight of the body of the carriage, and of 

 the load which it conveys. In ordinary carriages no other springs are 

 used ; but in those employed upon railways, springs are also used to 

 impart elasticity in the direction of the line of draught, so as to render 

 the starting and stopping of the carriages gradual and easy. 



SPRINGS. Rain and snow fall in quantities so unequal in different 

 districts, and on soils which exercise upon them such various influ- 

 ences, that the phenomena of springs, which are primarily dependent 

 on the penetration to some depth in the earth of water which was 

 absorbed at the surface, are extremely complicated and curious. It is 

 very interesting to geologists to classify and determine the causes of 

 these phenomena, and very important in agriculture and the arts to 

 acquire a power of directing the water currents in and below the soil 

 and strata. The art of draining consista essentially in giving to the 

 diffused and injurious springiness of particular soils and situations a 

 concentrated, perhaps beneficial, current ; while artesian wells relieve 

 the hydrostatic pressure prevalent at great depths, aud yield copious 

 streams iu dry lands and deserts. 



As a general rule, springs are permanent in proportion to the 

 depth to which the water which supplies them has descended from 

 thfi surface ; they are perennial and almost invariably constant in 

 temperature and volume, whether hot or cold, copious or fuh", in 

 situations where, from the arrangement of the mineral masses of the 

 globe, deep subterranean channels exist for the reception of rain, and 

 particular impediments direct and contract the passages of reflux to 

 the surface. Such cases are common in stratified countries whnv 

 jointed limestones or sandstones receive water at elevated points on the 

 surface, and conduct it downwards below strata of clay, which are only 

 pervious at a few points, and there permit natural discharges at lower 

 levels than the recipient surfaces. Frequently these argillaceous strata 

 are so nearly impervious, that artificial perforations relieve the pressure 

 of the subterranean columns of water better than the few natural 

 points of efflux, and thus pits and levels excavateil for mines may drain 

 springs at some distance. 



On the contrary, in a country which contains narrow and frequently 

 mixed masses of clay and gravel, or clay and sand, which cover the 

 solid rocks, concentrated springs are almost absent, but there is a 

 prevalent humidity and diffused springiness along the limit of the 

 gravelly or sandy tracts. After a continuance of thy v. eat her Mieh 

 springs and wetness disappear, to be renewed after the next fall of 

 rain. 



The particular points at the surface where springs, or "wells." a.^ 

 they are often called in the district* where .-..mewhat of the Saxon 

 elements of our language remains (qwllt, in German, signifying not 

 what is commonly understood by the English word " well," and the 



