In Hargreaves' machine the rovings were placed on the travelling carriage, and the twisting spindles in the fixed frame behind, a position which has never been acceptable since that time for cotton-spinning mules. Here, however, a word may be said in favour of Hargreaves' disposition of the parts mentioned. The Jenny did not contain any heavy drawing rollers and roller beams, and it was probably best in his machine to have his crude roving creel to traverse and the twisting spindles to be in a fixed frame.

This disposition of the parts is even now to be found in most Twiner Mules, that is, mules used to double two or more single threads together without any process of drawing being applied to the cotton.

When Crompton applied the principle of drawing rollers, his ingenious mind saw that it would be best to let the rollers, roller beam, and roving creel be in a fixed framework on account of their combined weight and size, making it very difficult to move them about.

Crompton's great idea seems to have been to produce a better thread by his machine than could be given by other machines, and in this he admirably succeeded.

The mule being set in motion, the rollers first attenuated and then delivered the cotton to the spindle carriage. The latter, by the action of the hand and knee, was made to recede from the rollers just about as fast as the cotton was delivered to the spindles, or possibly at a rather quicker rate. Then, while the thread was still in a soft state, the rollers could be stopped and the threads pulled still finer by the continued recession of the spindle carriage from the rollers.

Afterwards, when that length of thread was fully made, it wound on the spindles, and the carriage at the same time returned to the roller beam.

Thus each portion of thread was first subjected to the action of drawing rollers, as in Arkwright's machine, and then drawn still finer by the withdrawal of the travelling carriage, as in Hargreaves' Jenny.

Shortly after Crompton's invention was given to the public, it began to be improved in various ways. Henry Stones, a mechanic of Horwich, near Bolton, subst.i.tuted metal drawing rollers for Crompton's crude wooden rollers, doubtless copying the idea from Arkwright's water frame.

All the mules employed at first were necessarily short; by that is meant they contained but few spindles, often 40 or 50 spindles. The biggest mule in Bolton in 1786 was said to contain 100 spindles. The preparation of the rovings for the mule about this time occupied the attention of Crompton, and he invented a Carding Engine which, however, did not attain very much success. Indeed it is said that one day so incensed was Crompton at the way he had been treated on account of his mule, that he took an axe and smashed his engine to pieces.

In 1791 Crompton established a small manufactory in King Street, off Deansgate, in Bolton.

In 1800 a subscription, promoted mainly by Manchester gentlemen, resulted in 500 being handed over to Crompton, one of the contributors for thirty guineas being the son of Sir R. Arkwright. With this money he was enabled to enlarge his business somewhat--one of his new mules containing upwards of 360 spindles and another 220 spindles. The mules were worked for many years, in fact, up to the sixties, when they pa.s.sed into the hands of Messrs. Dobson & Barlow, the eminent cotton machinists of Bolton. One of the mules made by Crompton is shown in Fig. 24.

In the early part of 1812 an agitation for a government grant in recognition of Crompton's work made great progress. Mr. Perceval, the then Prime Minister, was proceeding to the House of Commons to move that a grant of 20,000 be made to Crompton, when he was shot by an a.s.sa.s.sin named Bellingham. There is no doubt, had this disastrous affair never happened and Perceval made his proposal, a grant much larger than was actually voted (5000) would have been made.

There is no doubt that this grant was altogether inadequate, seeing that larger sums had been voted to other investigators and inventors about this time.

Owing to his lack of business ability, and to ill fortune combined, poor Crompton did not get out of this money what he might have done. Several ventures turned out altogether very differently than he expected. He became poorer and poorer, and was only protected from absolute want by subscriptions and a.s.sistance provided by his true friends in the trade, notably Mr. Kennedy, a Manchester manufacturer.

Image: FIG. 25.--Portrait of Samuel Crompton. (_By the kind permission of W. Agnew & Son, Manchester._)

At the age of 74 he died, 26th June, 1827. He was interred in Bolton Parish Churchyard, where a plain granite tomb sets forth the following:--"Samuel Crompton of Hall ith Wood, Inventor of the Mule, born 3rd December, 1753, died 26th June, 1827."

A n.o.ble monument of him is to be found standing on Nelson Square, Bolton, in front of the General Post Office.

CHAPTER IX.

THE MODERN SPINNING MULE.

=The Self-Actor Mule.=--In the preceding chapter there has been detailed the particulars of the invention of the "Mule" by Samuel Crompton. Since that event the mule has been the object of over a century of constant and uninterrupted improvement and development, especially in the details of greater or less importance.

The Self-Actor Mule of to-day represents and embodies the inventions of hundreds of the most intelligent men ever connected with any industry in the world's history. It is universally acknowledged to be one of the most wonderful and useful machines ever used. The actual operations of making a thread are however practically as left by Samuel Crompton over a hundred years ago. It is only in details of mechanism involved in making the various operations more perfectly automatic, and of greater size and productiveness, that the long line of inventors since Crompton's first mule was made, has been engaged.

To-day, such is the great size and wonderfully perfect automatic action of these machines, that they are found 120 feet long, while in width, over all, they may be 9 or 10 feet. Such a mule of this length would contain over 1300 spindles, each spinning and winding 64 inches of thread in about 15 seconds, and one man with two youths would be sufficient to give all the attention such a machine required.

Independently of a vast number of inventors of smaller importance, there are several names which stand out in greater prominence in the history of the developments of the mule. Among these names must certainly be placed, ahead of any others that might be named, that of Richard Roberts of Manchester, who succeeded in 1830, after about five years'

application, in making the mule self-acting.

A good number of ingenious individuals had contributed more or less to this result between the dates of Crompton's and Roberts' inventions, and doubtless the results of the labours of these would be of great service to Roberts in his great task.

Indeed, several inventors had previously brought out what might be termed self-action mules, but it remained for Roberts to endow it with that constant and automatic motion which obtains to-day in practically the same form as left by him.

The special portion of mechanism with which his name is more especially identified, is what is denominated the "Quadrant." This is practically the fourth part of a large wheel, which is so arranged and connected that it performs almost exactly the same functions on a mule that Holdsworth's differential motion performs on the bobbin and fly frames.

To look at it, one would imagine it to be--what it really is--one of the simplest pieces of mechanism possible, yet the actions performed by it are complex and beautiful in the extreme. Later on, these actions of the Quadrant will be carefully examined.

Image: FIG. 26.--Mule head showing quadrant.

The self-actor mule is an intermittent spinning machine, _i.e._, it is not continuous in action, as are most machines used in the making of thread or yarn from the fibrous product of the Cotton plant. Take for instance the Carding Engine, and the bobbin and fly frames, as previously described. So long as these machines are working, practically all of the acting parts of the mechanism have a continuous forward motion.

This is by no means the case with the machine now under consideration, as many of the more important and princ.i.p.al parts move alternately in opposite directions, while other of the less important may revolve at one time, and be stationary at another.

What are called the medium counts of yarn contain say from 30 to 50 hanks in one pound avoirdupois; a cotton hank being equal to 840 yards, so that one pound of 40's yarn will contain no less than 40 840 yards or 33,600.

For such yarns as these, a modern self-actor mule would probably go through its cycle of movements four times per minute. For coa.r.s.er or thicker yarns this speed might be increased, while for finer and better qualities of yarn the speed would be diminished.

Now as each succeeding "stretch" marks a complete cycle of movements and is a repet.i.tion of others, it will probably suffice if a brief non-technical description of one of these "stretches" or "draws," as they are termed in mill parlance, be given.

As in the bobbin and fly frames, the bobbins containing the rovings of cotton to be operated upon, are placed behind the mules on skewers fitted in a suitable framework of wood and iron called "creels," so as to allow the cotton to be easily pulled off and unwound without breaking. These rovings are guided to and drawn through three pairs of drawing rollers (see Fig. 27), which shows this very fully.

The chief difference between these rollers and those of the previously described machines being in the lessened diameters of the mule rollers, and consequently attenuating the cotton to a much greater extent. It is a truism well understood by those in the trade, that the finer the rovings are the better the raw cotton must be, and the more drawing-out they will stand in any one machine. One inch of roving put up behind the rollers of a mule spinning medium numbers would probably be drawn out into 9 inches.

Image: FIG. 27.--Mules showing "stretch" of cotton yarn.

Nothing more need be said here about the action of the drawing rollers.

As the attenuated rovings leave the roller at the front, each one is conducted down to a spindle revolving at a high rate of speed; so quickly indeed, that there is no other body used in spinning which approaches it for speed.

It is quite a usual practice to have them making about 8000 revolutions per minute, and sometimes a speed of 10,000 is attained by them.

a.s.suming that a "Cop" of yarn (see Fig. 27), showing the cops on the spindles, has been partly made upon each spindle, the roving or thread from the rollers would extend down to the cop and be coiled round the spindle upwards up to the apex. The spindle would probably twist the thread for 40's counts twenty-three or twenty-four times for each inch that issued from the rollers, there being a well-recognised scale of "twists per inch" for various sorts and degrees of fineness of yarn.

Unlike the bobbin and fly frames, the roving or yarn is not wound on its cop or spindle as it is delivered, but a certain definite and regulated length of cotton is given out to each spindle, and fully twisted and attenuated before it is wound into a suitable shape for transit and for subsequent treatment.

To keep each thread in tension, therefore, as it is delivered from the rollers, the carriage containing the twisting spindles is made to recede quickly away from the rollers, a common distance for such movement being 64 inches. All the time the spindles are quickly revolving and putting twist into the rovings, thus imparting strength to them to a far greater degree than at any previous stage. Often the carriage is made to recede from the rollers a little quicker than the latter, the difference in the surface speeds between the two being technically known as "_gain_." The object of this carriage "gain" is to improve the "evenness" of the yarn by drawing out any thick soft places there may be in the length of thread between each spindle and the roller, a distance of 64 inches. It is a property of the twist that it will run much more readily into the thinner portions of thread than the thicker, thus leaving the latter capable of stretching out without breaking.

Arrived at the limit of 64 inches stretch (see Fig. 27), certain rods, levers, wheels and springs are so actuated that the parts which draw out the carriage and cause the rollers to revolve are disconnected, so that both are brought to a standstill for the moment.

In many cases the spindles at this stage are kept on revolving in order to put in any twist that may be lacking in any portion of the stretch.

Twisting being finished, the important operation of "backing off"

commences.

It maybe at once explained that "backing off" means the reversing of the spindles; the uncoiling of a portion of the yarn from the spindles; and generally putting all the requisite apparatus into position ready for winding or coiling the attenuated and twisted rovings upon the spindles.

Here come now into action those most beautiful and ingenious applications of mechanical principles, the working out of which entailed so many years of arduous effort, and which rendered the mule practically self-acting and automatic.

By a most wonderful, intricate and clever combination of levers, wheels, pulleys and springs, aided by what is called a "friction clutch," the instant the spindles have ceased twisting the yarn, they are reversed in direction of revolution.