By the end of the year, the 150 machines first made were sold off, and more orders were coming in. Thirty were wanted for exportation abroad, and a still greater number were wanted at home. The letter-copying machine gradually and steadily made its way, until at length there was scarcely a house of any extensive business transactions in which it was not to be found. Watt himself, writing of the invention some thirty years later, observed that it had proved so useful to himself that it had been worth all the trouble of inventing it, even had it been attended with no pecuniary profit whatever. Boulton’s principal business, however, while in town, was not so much to push the letter-copying machine, but to set straight the bankers’ account, which had been overdrawn to the amount of 17,000_l._ He was able to satisfy them to a certain extent by granting mortgages on the engine royalties payable in Cornwall, besides giving personal bonds for repayment of the advances within a given time. It was necessary to obtain Watt’s consent to both these measures; but, though Watt was willing to agree to the former expedient, he positively refused to be a party to the personal bonds.[190] Boulton was therefore under the necessity of arranging the matter himself. He was thereby enabled to meet the more pressing claims upon the firm, and to make arrangements for pushing on the engine business with renewed vigour. Watt was, however, by no means so anxious on this score as Boulton was. He was even desirous of retiring from the concern, and going abroad in search of health. “Without I can spare time this next summer,” he wrote, “to go to some more healthy climate to procure a little health, if climate will do, I must give up business and the world too. My head is good for nothing.”[191] While Boulton was earnestly pressing the invention on the mining interest, and pushing for orders, Watt shuddered at the prospect of one. He saw in increase of business only increase of headaches. “The care and attention which our business requires,” said he, “make me at present dread a fresh order with as much horror as other people with joy receive one. What signifies it to a man though he gain the whole world, if he lose his health and his life? The first of these losses has already befallen me, and the second will probably be the consequence of it, without some favourable circumstances which at present I cannot foresee should prevent it.”