Watt’s enforced confinement, together with his sedentary habits and unremitting labour, soon told upon his weak frame. When he hurried to his lodgings at night, his body was wearied, and his nerves exhausted, so that his hands shook like those of an old man; yet he persevered with the extra work which he imposed upon himself, in order to earn a little honest money to help to pay for his living. His seat in Mr. Morgan’s shop being placed close to the door, which was often opened and shut in the course of the day, he caught a severe cold in the course of the winter; and he was afflicted by a racking cough and severe rheumatic pains, from the effects of which he long continued to suffer. Distressed by a gnawing pain in his back, and greatly depressed in spirits, he at length, with his father’s sanction, determined to return to Greenock, to seek for renewal of health in his native air. His father made him a further remittance to enable him to purchase some of the tools required for his trade, together with materials for making others, and a copy of Bion’s work on the construction and use of Mathematical Instruments. Having secured these, he set out on his return journey for Scotland, and reached Greenock in safety in the autumn of 1756. There his health soon became sufficiently restored to enable him to return to work; and with the concurrence and help of his father, he shortly after proceeded to Glasgow, in his twentieth year, to begin business on his own account. In endeavouring to establish himself in his trade, Watt encountered the same obstacle which in London had almost prevented his learning it. Although there were no mathematical instrument makers in Glasgow, and it must have been a public advantage to have so skilled a mechanic settled in the place, Watt was opposed by the corporation of hammermen on the ground that he was neither the son of a burgess nor had served an apprenticeship within the borough.[65] Failing in his endeavours to open a place of business, he next tried to prevail on the corporation to allow him to make use of a small workshop wherein to make experiments; but this also was peremptorily refused. The hammermen were doubtless acting in a very narrow spirit, in thus excluding the young mechanic from the privileges of citizenship; but such was the custom of the times,--those who were within the favoured circles usually putting their shoulders together to exclude those who were without. Watt had, however, already been employed by Dr. Dick, Professor of Natural Philosophy, to repair some mathematical instruments which had been bequeathed to the University by a gentleman in the West Indies; and the professors, having an absolute authority within the area occupied by the college buildings, determined to give him an asylum there, and thus free him from the incubus of the guilds.