labour required being that of a few boys and girls to watch them and
mend the broken threads when the carriage recedes from the roller beam,
and to stop it when the cop is completely formed, as is indicated by
the bell of the counter attached to the working gear. Mr. Baines
describes the self-acting mule while at work as "drawing out, twisting,
and winding up many thousand threads, with unfailing precision and
indefatigable patience and strength--a scene as magical to the eye
which is not familiarized with it, as the effects have been marvellous
in augmenting the wealth and population of the country." [5]

Mr. Roberts's great success with the self-acting mule led to his being
often appealed to for help in the mechanics of manufacturing. In 1826,
the year after his patent was taken out, he was sent for to Mulhouse,
in Alsace, to design and arrange the machine establishment of Andre
Koechlin and Co.; and in that and the two subsequent years he fairly
set the works a-going, instructing the workmen in the manufacture of
spinning-machinery, and thus contributing largely to the success of the
French cotton manufacture. In 1832 he patented his invention of the
Radial Arm for "winding on" in the self-acting mule, now in general
use; and in future years he took out sundry patents for roving,
slubbing, spinning, and doubling cotton and other fibrous materials;
and for weaving, beetling, and mangling fabrics of various sorts.

A considerable branch of business carried on by the firm of Sharp,
Roberts, and Co. was the manufacture of iron billiard-tables, which
were constructed with almost perfect truth by means of Mr. Roberts's
planing-machine, and became a large article of export. But a much more
important and remunerative department was the manufacture of
locomotives, which was begun by the firm shortly after the opening of
the Liverpool and Manchester Railway had marked this as one of the
chief branches of future mechanical engineering. Mr. Roberts adroitly
seized the opportunity presented by this new field of invention and
enterprise, and devoted himself for a time to the careful study of the
locomotive and its powers. As early as the year 1829 we find him
presenting to the Manchester Mechanics' Institute a machine exhibiting
the nature of friction upon railroads, in solution of the problem then
under discussion in the scientific journals. In the following year he
patented an arrangement for communicating power to both