This statement is dated December 23rd, 1834, so that it may fairly serve as a basis of comparison, assuming the number of turns of yarn to be in each case the same. Testing the advance by taking the production of 32’s, as stated above, the amount spun per spindle in a working week of 501⁄2 hours—its present duration—would be 182⁄3 hanks. Mules at that period were only made 400 to 500 spindles long. To-day they contain over 1,200 spindles, and produce of 32’s 321⁄2 hanks per spindle. This is an increase of 60 per cent.
(5) The increase of production has not, however, required a larger number of workpeople to obtain. On the other hand, fewer persons are needed to attend to the long mules named than were formerly required for less than half the number of spindles. The effect of this is seen in the decreased margin between cotton and yarns, which is very striking. The average price of 30’s twist yarn in 1832 is stated in Dr. Ure to be 12·7d. per lb., and of cotton 7·1d., leaving a margin of 5·6d. At the time of writing the price of 32’s twist is 811⁄16d., and of cotton 69⁄16d. per lb., leaving a margin of 21⁄8d. These figures are based upon the assumption that American cotton of middling quality is used in each case. Thus the price of yarn is much less, while that of cotton is little reduced. It is true that a margin of 21⁄8d. is barely sufficient to permit of a profit being made, but 1⁄8d. per lb. added will do 80, and a margin of 21⁄2d. is considered a large one in these days.
(6) This reduction in the cost of production has not been brought about by any diminution in the wages of the operatives, as could very clearly be shown if it were necessary. Nor is it the result of a lessened cost of erection. A spinning mill of 40,000 spindles, which in 1835 would be looked upon as a large one, cost, at that time, from 24 to 26 shillings per spindle to erect, including the buildings and accessories. At the present time mills are built to contain as many as 110,000 spindles, and these are filled ready for work at a cost not exceeding 21 shillings per spindle, the apportionment of which is as follows: The machinery costs nine shillings, the buildings eight shillings, and the engines, boilers, furnishings, and all accessories four shillings per spindle. Considering the great increase in the productive power of the machinery, the fact that it is so much less expensive to work, and that each machine is of much greater capacity, the figures given show that the tendency towards diminished cost is owing very largely to the efforts of machine makers.
(7) It is not necessary to pursue this matter further, as the present work is not intended as a statistical abstract, but the few facts stated show that in the general march of improvement the textile mechanic has not been idle. A consideration of the methods of construction adopted to-day, as compared with those in vogue even so recently as twenty years ago, will further demonstrate this fact. Formerly the work of construction was very largely if not mainly carried out by fitters who were engaged in manually shaping the brackets and fitting them to the frames. The brackets were formed with feet, on which were cast nipples or projections. These were used to reduce the labour in filing, and, as the bracket was always fitted on to the face produced in the ordinary operation of casting, it will be seen that anything tending to diminish the work of fitting was valuable. But as the bedding of the brackets was dependent upon the proper shaping of a few points, the tendency to slip was considerable. Although, by being always engaged in fitting a few patterns of brackets, the workmen became extraordinarily expert, the method was at best an uncertain one, and did not lead to the rigidity absolutely essential in high-speed machines.
(8) All this is now changed, and the machine tool enables the work to be at once more expeditiously and economically carried out. The labours of mechanics of precision, like the late Sir Joseph Whitworth, are bearing fruit, and the effect is seen in the comparative excellence of the product. The solidity of English machinery has been sometimes scoffed at by Continental and American rivals, but it would be difficult to find any which runs at higher velocities with greater steadiness and less repairs. It cannot be too often insisted on that the rigidity which arises from mere weight is by no means an unimportant quality. Of course, there are limits to this as to every other principle, but generally it is a true one. Of quite as much importance is the rigidity which comes from sound construction; and in this respect modern spinning machinery is remarkable. Instead of a framing built up by hand with its various pieces manually fitted, it is now made in a much more enduring way. Raised faces are formed on the framing, which are planed or milled, so as to be quite true. To these the cross-beams or bars, the ends of which are similarly treated, are bolted. Thus, instead of the contact of several narrow faces, two broad plane surfaces are bolted together, and it will be easily seen how much more solid the framing will be in consequence. Again, in lieu of each part being at once like and unlike, as must necessarily happen when it is hand-fitted, it is now shaped by special machinery to templates, thus being interchangeable. The rails or beams to which bearings, brackets, or spindles are to be attached are planed or milled accurately on their surfaces, so that the long and unsatisfactory labour of fitting each piece separately is substituted by a true mechanical process. The advent of the milling machine and the discovery of the wonderful economic power of the circular cutter has had a wide-reaching influence. In brief, the present is an age of an increased development of machine instead of manual treatment, which has gone far to revolutionise the machinery used in spinning. Every student who may hereafter be engaged in the construction of this class of machinery should impress firmly upon his mind the fact that the machine tool is the best instrument for his purpose, and should develop it as far as possible. A special tool is invaluable, and the opportunities for its use are always increasing.
(9) A comparison of the speeds of various machines will demonstrate the value of improved construction. Mule spindles, which in 1834 were run at a maximum velocity of 4,500 revolutions per minute, are now revolved 11,000 times per minute with much greater ease and freedom from vibration. The throstle spindles running at a speed of 4,500 revolutions, are superseded by ring spindles, which rotate from 9,000 to 11,000 times per minute. As shown in Chapter [XII], it would be impossible to attain such a velocity unless the spindles were accurately constructed by special tools. Although the mechanism of a ring spindle is much more elaborate than that of a throstle spindle, the cost of the one but little exceeds that of the other. Again, a carding engine cylinder, formerly made of wood, and running 80 to 100 revolutions, is now constructed entirely of iron, and revolved at from 160 to 180 times per minute. In spite of this increase it is more free from vibration than its slower running predecessor. A similar comparison can be made of every machine with like results, but it is not necessary. Enough has been said to show the important part played by the machinist, to whom, as was pointed out in paragraph 1, most of the credit is due. The economical improvement which is noticeable in the condition of the workpeople is largely the result of the improvements made in the machinery. In fewer hours more work can be turned out, and this with a constantly decreasing strain upon the operatives. The breakage of the fibres in the various stages of manufacture is reduced to a very low point, with the twofold advantage of diminished waste and decreased labour.
(10) A modern mill differs from its immediate predecessor, not only in the quality of the machinery but in its general construction. The height and width of the whole building have materially increased, and the result is that the rooms in which the operations of spinning are conducted are both lighter and more airy. The building is usually made as far as possible fire-proof, and is of very substantial design and construction. The larger number of spindles in a mill necessarily imply greater capacity, but there is no comparison between the low-ceilinged, imperfectly lighted and ventilated rooms of the last generation with the airy and light erections of to-day. The sanitary arrangements are infinitely superior, and there is a noticeable improvement in the health and physique of the workpeople arising therefrom.
(11) Among the features which deserve mention is the improved type of engines used. In lieu of the old-fashioned beam engine, compounded or otherwise, working at a steam pressure of 50lb. or less, the modern engine is of the horizontal type. The favourite class for mill driving is the tandem compound, in which the high pressure cylinder is behind the low-pressure, but on the same bed. Latterly the vertical triple expansion engine has been adopted in a few cases, and there is a continual tendency towards higher steam pressures and more expansions. The introduction of steel boiler plates has rendered the construction of steam boilers for high pressures much more easy, and the author has seen a Lancashire boiler, intended for habitual use at a pressure of 220lb., tested with highly satisfactory results. Within limits, therefore, there is room for a further increase from the normal working pressure of 80lb. The steam-engines used are mostly of the Corliss type, with quick cut-off gear of high efficiency, and they are constructed to develop in many cases from 1,000 to 2,000 horsepower. The water used for condensing purposes is stored in reservoirs or “lodges,” from which it is drawn as required. It is sometimes difficult to cool it sufficiently to get a good vacuum, owing to the fact that the cooling and storage space is insufficient. For this purpose a type of condenser known as Theisen’s, which has been largely adopted in Germany and is now being introduced into this country, will be of value. It is arranged as a surface condenser, the steam passing through the tubes and being cooled by water surrounding them. In lieu of giving the water a circulatory movement it always remains in one position, any loss by evaporation being replaced. Between each vertical row of pipes cast-iron discs revolve, which are fixed on a shaft suitably driven. As each disc dips into the water—which is usually about 160 deg. F.—it picks up a thin film and carries it round in its revolution. At the upper part of the case, in which the discs revolve, an air propeller is fixed, which sends a current of air past and through the spaces between the discs. This leads to a rapid cooling of the disc and its water film, the heat absorbed by the water being in this way dissipated. The action is one of evaporative cooling, of which many instances abound, and is very effective. An equal weight of water will effectually condense any given volume of steam, and this quantity is not difficult to find in most places. The results obtained by the Union Engineering Company in this country have been satisfactory, and there appears to be no doubt as to the efficacy of the machine. Steadiness of rotation is a sine qua non in mill engines, a very slight difference in their velocity having a great effect upon the work of the mill. This is now attained in most cases with certainty, and by means of the Moscrop Recorder—an instrument denoting graphically the changes of speed—a very salutary check is kept upon the engineer. In order to prevent any variations occurring high-speed governors are largely employed, and in some cases their action is aided by special means, such as Knowles’s supplementary governor or Higginson’s patent regulator. Either of these appliances give good results, and the last named is very simple and effective.
(12) Up to within 15 or 20 years ago the most common mode of transmitting the power developed by the steam engine was by means of toothed gearing. About that period the American method of driving by a series of broad belts was introduced and for a time was largely adopted. When toothed gearing was used the power was conveyed to the various flats or storeys of the mill by means of an upright shaft, on which were bevel wheels gearing with others on the line shafts. The introduction of belt driving led to a system of transmitting the power to the main shaft in each room independently of its fellows, and this system found further development when driving by a series of ropes was adopted a short time afterwards. In this case the power is taken off by a number of ropes working in the grooves of a large pulley on the engine shaft and of smaller ones fixed on the line shafts. This is now the favourite method of driving and is more extensively adopted than any other. The reason for this is principally the ease with which breakdowns can be guarded against. If a rope breaks it falls into the race, and in rare instances does it become entangled. It is only necessary to replace it, and any delay thus caused is not great.