By this time Roebuck was becoming embarrassed with debt, and involved in various difficulties. The pits were drowned with water, which no existing machinery could pump out, and ruin threatened to overtake him before Watt’s engine could come to his help. He had sunk in the coal-mine, not only his own fortune, but much of the property of his relatives; and he was so straitened for money that he was unable to defray the cost of taking out the engine patent according to the terms of his engagement, and Watt had accordingly to borrow the necessary money from his never-failing friend, Dr. Black. He was thus adding to his own debts, without any clearer prospect before him of ultimate relief. No wonder that he should, after his apparently fruitless labour, express to Small his belief that, “of all things in life, there is nothing more foolish than inventing.” The unhappy state of his mind may be further inferred from his lamentation expressed to the same friend on the 31st of January, 1770. “To-day,” said he, “I enter the thirty-fifth year of my life, and I think I have hardly yet done thirty-five pence worth of good in the world; but I cannot help it.” Notwithstanding the failure of his engine thus far, and the repeated resolution expressed to Small that he would invent no more, leading, as inventing did, to only vexation, failure, loss, and increase of headache, Watt could not control his irrepressible instinct to invent; and whether the result might be profitable or not, his mind went on as before, working, scheming, and speculating. Thus, at different times in the course of his correspondence with Small, who was a man of a like ingenious turn of mind, we find him communicating various new things, “gimcracks,” as he termed them, which he had contrived. He was equally ready to contrive a cure for smoky chimneys, a canal sluice for economising water, a method of determining “the force necessary to dredge up a cubic foot of mud under any given depth of water,” and a means of “clearing the observed distance of the moon from any given star of the effects of refraction and parallax;” illustrating his views by rapid but graphic designs embodied in the text of his letters to Small and other correspondents. One of his minor inventions was a new method of readily measuring distances by means of a telescope.[88] At the same time he was occupied in making experiments on kaolin, with the intention of introducing the manufacture of porcelain in the pottery work on the Broomielaw, in which he was a partner. He was also concerned with Dr. Black and Dr. Roebuck in pursuing experiments with the view of decomposing sea-salt by lime, and thereby obtaining alkali for purposes of commerce. A patent for the process was taken out by Dr. Roebuck, but eventually proved a failure, like most of his other projects. We also find Watt inventing a muffling furnace for melting metals, and sending the drawings to Mr. Boulton at Birmingham for trial. At other