Messrs. J. & H. McLaren, of the Midland Engine Works, Hunslet, Leeds, England, for several years past have devoted considerable attention to the question of mounting traction engines on springs. The outcome of this is the engine in question, the front end of which is carried by a pair of Timmis spiral springs, resting on the center pin of the front axle, which is on Messrs. McLaren's principle, which enables it to accommodate itself to the inequalities of the road without throwing any undue strain on the front carriage. The chief difficulty hitherto has been to mount the hind end on springs without interfering with the spur gearing, which must be kept perfectly rigid to prevent breakage of the cogs. This is entirely provided for by the new arrangement, whereby all the spring is allowed for in the spokes of the wheel itself, which will be clearly seen on reference to the illustrations, in which Fig. 1 is a perspective view of the engine, while Fig. 2 shows a detail view of the wheel. The rim of the wheel is built up in the ordinary way of strong T-iron rings, with steel crossplates riveted on. The nave of the wheel has wrought-iron ribs to which the spokes are bolted.

These spokes are made of the best spring steel, specially manufactured and rolled for the purpose, 9 inches wide and ½ inch thick. They are bent in a pear shape, with the narrow ends fastened to the nave, and the crown resting upon the rim of the wheel, where they are divided, and held in their places by means of clip fastened with bolts. When the weight of the engine comes on these spokes, those nearest the ground are compressed and those, at the top are elongated a little. In order to avoid any of the driving strain passing through the springs, a strong arm is fixed on the differential wheel and attached to the rim as shown in Fig. 2, so that the springs have really no work to do beyond carrying the weight of the engine. Messrs. McLaren naturally felt a certain amount of diffidence in placing their invention before the public until they had thoroughly tested it in practical work. This, we are informed, they have done, with the most satisfactory results, during the last five or six months; and they have a set of springs which ran during that time between 2,000 and 3,000 miles, besides which there are several of these spring engines in daily use.--Iron.

FIG 1. IMPROVED SPRING TRACTION ENGINE.

FIG 1. IMPROVED SPRING TRACTION ENGINE.

Improved Spring Traction Engine 401 4c

FIG. 2

Table Showing The Relative Dimensions, Lengths, Resistances, And Weights Of Pure Copper Wire

 DIAMETER | AREA

|

B.W.G Inch. Milli- | Circu- Square Square

No. metres | lar inches. Milli-

| Mils. metres.

|

0000 .454 11.5313 | 206116 .161883 10.4435

000 .425 10.795 | 180625 .141862 9.152

00 .38 9.6518 | 144400 .113411 7.3165

0 .34 8.6358 | 115600 .0907922 5.8573

1 .3 7.620 | 90000 .070686 4.5602

2 .284 7.2134 | 80656 .0633472 4.0867

3 .259 6.5784 | 67081 .0526854 3.3989

4 .238 6.0451 | 56644 .0444881 2.8701

5 .22 5.5879 | 48400 .0380133 2.4523

6 .203 5.1561 | 41209 .0323655 2.088

7 .18 4.5719 | 32400 .0254469 1.6417

8 .165 4.1909 | 27225 .0213825 1.3794

9 .148 3.7591 | 21904 .0172034 1.1098

10 .134 3.4035 | 17956 .0141026 .9096

11 .12 3.0479 | 14400 .0113097 .7296

12 .109 2.7701 | 11881 .00933133 .60199

13 .095 2.4129 | 9025 .0070882 .4573

14 .083 2.1082 | 6889 .00541062 .34906

15 .072 1.8288 | 5184 .00407151 .2486

16 .065 1.6510 | 4225 .00331831 .21407

17 .058 1.4732 | 3364 .0026421 .17045

18 .049 1.2446 | 2401 .00188574 .12165

19 .042 1.0668 | 1764 .00138544 .0894

20 .035 0.8890 | 1225 .000962115 .06207

21 .032 0.8128 | 1024 .00080425 .05188

22 .028 0.7112 | 784 .000615753 .03972

23 .025 0.635 | 625 .00049087 .03167

24 .022 0.5588 | 484 .000380133 .02452

25 .02 0.508 | 400 .00031416 .02027 
26 .018 0.4571 | 324 .000254469 .01642 27 .016 0.4064 | 256 .000201062 .01297 28 .014 0.3556 | 196 .000153938 .00993 29 .013 0.3302 | 169 .000132732 .00856 30 .012 0.3048 | 144 .000113097 .007296

LENGTH AND WEIGHT

 B.W.G Pounds Pounds Pounds Pounds Feet Yards 1.000 feet Miles

No. per per per 1.000 per per lb. per lb. per lb. per lb.

foot. Yard ft. mile. 
0000 .623924 1.871772 623.924 3294.32 1.60276 .534253 .00160276 .00303553 000 .54676 1.64028 546.76 2886.89 1.82895 .60965 .00182895 .0034639 00 .437105 1.311315 437.105 2307.92 2.28777 .76259 .00228777 .004333 0 .349928 1.049784 349.928 1847.62 2.85773 .9525766 .00285773 .0054124 1 .272435 .817305 272.435 1438.43 3.6706 1.22353 .0036706 .0069519 2 .244151 .732453 244.151 1289.11 4.0958 1.365266 .0040958 .0077573 3 .203058 .609174 203.058 1072.15 4.9247 1.641566 .0049247 .009327 4 .171463 .514395 171.465 905.333 5.8321 1.944033 .0058321 .0110457 5 .14651 .43953 146.510 773.56 6.8255 2.275166 .0068255 .012927 6 .124742 .374226 124.742 658.638 8.0165 2.672166 .0080165 .015183 7 .098076 .294228 98.076 517.844 10.1962 3.39873 .0101962 .019311 8 .082411 .247233 82.411 435.135 12.1345 4.04483 .0121345 .022981 9 .066305 .198915 66.305 350.089 15.0818 5.027266 .0150818 .028564 10 .054354 .163062 54.354 286.99 18.398 6.13266 .018398 .034845 11 .04359 .13077 43.590 230.152 22.9413 7.6471 .0229413 .04345 12 .035964 .107892 35.964 189.893 27.805 9.2683 .027805 .05266 13 .027319 .081957 27.319 144.245 36.6046 12.20153 .0366046 .069326 14 .020853 .062559 20.853 110.1088 47.954 15.98466 .047954 .09082 15 .015692 .047076 15.692 82.855 63.7267 21.24223 .0637261 .12069 16 .012789 .038367 12.789 67.5276 78.1902 26.0634 .0781902 .14809 17 .0101828 .0305484 10.1828 53.7665 98.202 32.734 .098203 .18589 18 .00726795 .02180388 7.26796 38.3748 137.590 45.8633 .137590 .260587 19 .00533972 .01601916 5.33972 28.1937 187.276 62.4253 .187276 .35469 20 .00370815 .01112445 3.70815 19.579 269.676 89.892 .2696676 .51075 21 .00309972 .00929910 3.09972 16.3665 322.610 107.5366 .322610 .61100 22 .00237312 .00711936 2.37312 12.5301 421.384 140.4613 .421334 .798078 23 .0018910 .0056757 1.8919 9.9892 528.570 176.190 .528570 .100108 24 .0014650 .0043950 1.4650 7.7357 682.55 227.5166 .68255 .129271 25 .00121082 .00363246 1.21082 6.39315 825.880 275.2943 .825883 .156417 26 .00098077 .00294231 .98077 5.17844 1019.61 339.870 1.01961 .193108 27 .00077492 .00232476 .77492 4.0916 1290.44 430.1466 1.29044 .24440 28 .0005933 .0017799 .5933 3.13264 1685.48 561.8266 1.68548 .31922 29 .000511571 .001534713 .511571 2.7011 1954.76 651.5866 1.95476 .370220 30 .0004359 .0013077 .4359 2.30152 2294.13 764.710 2.29413 .434496

LENGTH AND RESISTANCE

 B.W.G Feet Yards 1.000 feet Miles Ohms Ohms Ohms Ohms

No. per Ohm. per Ohm. per Ohm. per Ohm. per foot. per yard. per 1.000 per mile.

foot. 
0000 19966.5 6655.5 19.9665 3.7815 .000050684 .00156252 .050084 .264443 000 17497.15 5832.3833 17.49715 3.31385 .0000571522 .0001714566 .0571522 .301763 00 13988.64 4662.68 13.98804 2.64925 .000071489 .000214467 .071489 .377465 0 11198.17 3732.7333 11.19817 2.12086 .0000893002 .0002679006 .0893002 .471505 1 8718.30 2906.10 8.71830 1.6512 .00011470 .0003441 .114701 .60562 2 7813.50 2604.50 7.81350 1.47973 .00012799 .00038397 .12799 .67580 3 6498.14 2166.0466 6.49814 1.23071 .00015389 .00046167 .15389 .81254 4 5487.107 1829.0357 5.487107 1.03923 .000182245 .000546735 .182245 .962256 5 4688.51 1562.8366 4.68851 .887975 .000213287 .000639861 .213287 1.12616 6 3991.91 1330.6366 3.99191 .756045 .000250506 .000751518 .250506 1.32267 7 3138.59 1046.1966 3.13859 .59443 .000318614 .000955842 .318614 1.68228 8 2637.29 879.0966 2.63729 .499486 .000379177 .001137531 .379177 2.00206 9 2121.84 707.280 2.12184 .401864 .000471289 .001413867 .471289 2.488405 10 1739.40 579.80 1.73940 .329432 .000574911 .001724733 .574911 3.03553 11 1394.93 464.9766 1.39493 .264191 .000716882 .002150646 .716882 3.78514 12 1150.91 383.6366 1.15091 .217976 .000868875 .002606625 .868875 4.58766 13 874.252 291.4173 .874252 .165578 .00114383 .00343149 1.14383 6.03945 14 667.338 222.446 .667338 .12639 .00149849 .00449547 1.49849 7.91203 15 502.175 167.39166 .502175 .095109 .00199134 .00597402 1.99134 10.5142 16 409.276 136.42533 .409276 .077514 .00244334 .00733002 2.44334 12.9008 17 325.871 108.62366 .325871 .061718 .0030687 .0092061 3.0687 16.20274 18 232.585 77.52833 .232585 .04405 .0042995 .0128985 4.2995 22.7014 19 170.879 56.95966 .170879 .032363 .0058521 .0175563 5.8521 30.8991 20 149.3915 49.797166 .1493915 .022475 .00842703 .02528109 8.42703 44.4947 21 99.195 33.065 .099195 .018787 .01008110 .03024348 10.08116 53.2285 22 75.9461 25.315366 .0759461 .014384 .0131672 .0395016 13.1672 69.5230 23 60.54377 20.181256 .06054377 .011467 .0165170 .0495510 16.5170 87.2096 24 46.8851 15.628356 .0468851 .0088798 .02132874 .06398622 21.32874 112.616 25 38.748 12.916 .038748 .0073386 .025808 .077424 25.808 136.265 26 31.3859 10.461966 .0313859 .0059443 .03186144 .09558432 31.86144 168.229 27 24.79873 8.266243 .02479873 .0046967 .0403246 .1209738 40.3246 212.914 28 18.98653 6.328843 .01898653 .0035959 .05266892 .15800676 52.66892 278.092 29 16.3710 5.4570 .0163710 .0031006 .0610834 .1832502 61.0834 322.521 30 13.9493 4.649766 .0139493 .0026419 .07168825 .21506475 71.68825 378.514

RESISTANCE & WEIGHT

 B.W.G Ohms Lbs.

No. per lb. per Ohm. 
0000 .000080272 12457.5 000 .000104529 9566.7 00 .000163553 6114.24 0 .000255196 3918.58 1 .00042102 2375.18 2 .00052422 1907.59 3 .00075786 1319.50 4 .0010629 940.844 5 .0014558 686.911 6 .0020082 497.96 7 .00324863 307.822 8 .00460101 217.343 9 .00710791 140.689 10 .0105772 94.543 11 .0164462 60.842 12 .0241593 41.392 13 .0418692 23.8839 14 .0718583 13.9163 15 .126788 7.8872 16 .191045 5.2344 17 .301355 3.31835 18 .59157 1.6904 19 1.09596 .912445 20 2.27254 .44003 21 3.25229 .30748 22 5.54843 .18023 23 8.73035 .11454 24 14.5579 .068691 25 21.3142 .046917 26 32.4863 .030782 27 52.0367 .019217 28 88.7724 .011265 29 119.404 .008375 30 164.4762 .0060804

PURE COPPER weighs 555 lbs. per cubic foot. The Resistance of 1 mil. foot at 60° Fahr. is, according to Dr. Matthiessen, 10.32311 ohms. Upon these data the above Table has been calculated.

The Resistance of Copper varies with the temperature about 0.38 per cent. per degree Centigrade, or 0.21 per cent. per degree Fahrenheit.

Stranded Wires

With a conductor of a definite lenght, made of Stranded Wires, the total weight is greater, and the Resistance less than is a similar length of Conductor with Wires not Stranded.

 To convert--Inches to Millimetres multiply by 25.3994

Feet to Metres " .3048

Yards to Metres " .9144

Miles to Kilometres " .6214

Pounds to Kilogrammes " .45359 

PEPARED BY WALTER T. GLOVER & CO., ELECTRICAL WIRE AND CABLE MAKERS, 25, BOOTH STREET MANCHESTER.