Chapter 3

We must remark that the hypochlorites require a certain length of time to permit the chlorine to become disengaged, and that, besides, all chlorides, bromides, and iodides that are isomorphous are capable of undergoing an analogous chemical transformation and of being employed for the same purpose. This is especially the case with the chlorides of potassium or barium, the bromides of strontium or calcium, and the iodides of aluminum or magnesium. On another hand, as sea water contains different chlorides, it results that it might serve directly as a raw material for bleaching textile fibers. Then, when the solution of chloride of sodium has been deprived of its chlorine by electrolysis, there remains a solution of caustic soda which may be utilized for scouring fibers.--_H. Danzer, in Le Génie Civil_.

* * * * *

IMPROVED SPRING TRACTION ENGINE.

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_.

* * * * *

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.

* * * * *

IRON FRAME GANG MILLS.

The gang mill is regarded as possessing material advantages in the rapid and economical manufacture of lumber. Among the recent improvements tending to perfect such mills, those which are shown in the iron frame stock gang, manufactured by Wickes Bros., East Saginaw, Mich., are eminently valuable. Our large engraving represents one of these mills, constructed to be driven by belt, friction, or direct engine, as may be desired. The important requisite in this class of mills is such design and proportion of parts as will insure durability and continued movement at the highest speed, safely increasing the quantity and improving the quality of work done at a lesser feed, and admitting the use of thinner saws than is practical in the slower moving sash. These are among the advantages gained in the iron frame machine, overcoming the necessity of an expensive mill frame, saving time and expense in setting up, and avoiding the liability of decay or change of position.

Many improvements have been made in the mechanism of oscillation, and from these the builders of this mill have adopted what is known as the Wilkin movement, which oscillates the top and bottom slides. The top slides are pivoted at the top end, and the bottom ones from the bottom end, both being operated by one rock shaft from the center. This movement when properly adjusted gives an easy clearance and the easiest cut yet obtained. It adds no extra weight to the sash, and avoids the cumbrous rock shaft and its attendant joints, usually weighing from three hundred to five hundred pounds, which have been found so objectionable in many other movements. The feed is continuous, and is made variable from ¼ to 1¼ inch to each stroke, controllable by the sawyer. Power is applied to the press rolls in the double screw form with pivot point, also operated by the same hand. A special feature of this machine is the spreading of the lower frame so that its base rests upon an independent portion of the foundation from the main pillow block or crank shaft. The solidity of the whole structure is thus increased, both by the increased width at the base and the prevention of connecting vibrations, which necessarily communicate when resting upon the same part, as in other forms of such machines heretofore in use.

The mill shown in the perspective view is one of twenty-six saws 4½ feet long, sash 38 inches wide in the clear, and stroke 20 inches, capable of making 230 strokes per minute. The crank shaft is nine inches in diameter, of the best forged iron. The main pillow block has a base 6½ feet long by 21 inches bearing, weighing 2,800 pounds. The cap is secured by two forged bolts 3½ inches in diameter, and by this arrangement no unequal strain upon the cap is possible. A disk crank is used with suitable counterbalance, expressly adapted to the weight and speed of sash; a hammered steel wrist pin five inches in diameter, and a forged pitman of the most approved pattern, with best composition boxes. The iron drive pulley is 4 to 4½ feet in diameter and 24 inches face; the fly-wheel six feet in diameter, and weighing 4,700 pounds, turned off at rim. When a wider and heavier sash is required, a proportionate increase is made in all these parts.

In the construction of the sash the stiles are made of steel; the lower girt and upper heads are made in one solid piece, without rivets, giving the greatest strength possible, with the least weight. The outfit also includes eight iron rollers for the floor, 8½ inches in diameter, with iron stands, and geared as live rolls when desired, a full set of Lippencott's steel saw hangings, and gauges for one-inch lumber. The weight of the machine here shown is 18½ tons. They are, however, built in larger or smaller sizes, adapted to any locality, quality or quantity of work desired.

* * * * *

It is said that the St. Gothard Tunnel is diverting the bulk of the Italian trade into the hands of the Belgians, Germans, and Hollanders with startling rapidity. Without breaking bulk, early fruits are taken from all parts of Italy to Ostend, Antwerp, and Rotterdam, whence they are carried by fast steamers to London and other English ports. But, on the other hand, Germany is sending into Italy large quantities of coal, iron, machinery, copper, and other articles of which the latter received nothing before. In two months alone, the Italians imported 1,446 tons of paper.

* * * * *

THE HEAT REGENERATIVE SYSTEM OF FIRING GAS RETORTS.

The system of heat regeneration in the firing of gas retorts, in accordance with the principle which Dr. C.W. Siemens has worked out in such a variety of ways in the industrial arts, has lately been applied with very marked success at the Dalmarnock Station of the Glasgow Corporation Gas Works. Notwithstanding the fact that a period of about twenty years has elapsed since Dr. Siemens successfully adapted his system to the firing of retorts at the Paris Gas Works, it seems to have made but little progress up to the present time; for what reasons it is perhaps difficult to explain. It is certain, however, that so-called regenerator furnaces of various forms have, from time to time, been brought into use at gas works for the purpose in question both on the Continent and in this country; and in recent years the subject has received much attention from gas engineers, the general opinion eventually being that the adoption of such a system of working would be certain to result in so great an amount of economy as to put gas as an illuminating agent on a more secure footing to compete successfully with its modern and somewhat aggressive rival, the electric light. Of course, it is now admitted that the mode of adapting the heat regenerative principle at the Paris Gas Works was attended with a degree of complexity in the structural arrangements that was so great and so expensive as to place it practically beyond the reach of gas companies and gas corporations generally, when the expense as well as the scientific beauty and practical efficiency of the new mode of applying and utilizing heat had to be considered. Fortunately, however, Dr. Siemens was enabled two or three years ago to demonstrate that there was no such thing as "finality" in that department of invention which he had made almost exclusively his own. About the time mentioned he placed his most advanced views on gas producers and on the regeneration and utilization of heat before the world, and within that period a most decided step in advance has been made, the structural arrangements now required for gas producers and regenerator furnaces having been immensely simplified and cheapened, while their practical utility has in no way been interfered with.

Scarcely had Dr. Siemens announced his new form of gas producer and regenerator than communication was opened with him by Mr. W. Foulis, the general manager to the Glasgow Corporation Gas Trust, with the view of entering into arrangements for its adoption on an experimental scale at one of the stations under his charge. Encouraged by the hearty co-operation of the gas committee, two or three of whose members were well known engineers, Mr. Foulis very soon came to an understanding with Dr. Siemens to have the regenerative system put to a thorough test at the Dalmarnock Gas Works, situated in the extreme east end of the city, and the largest establishment of the kind in Scotland, the total number of retorts erected being about 750. The system in its most recent shape was applied to four ovens, each of which had seven retorts, but which number has since been increased to eight, owing to the space occupied by the furnace in the ordinary settings being rendered available for an additional retort in the new or "Siemens" setting. For each oven or chamber of eight retorts there was erected a separate gas-producer, so that even one set of eight retorts might alone be used if thought necessary.