[192] Boulton, at Plengwarry, to Watt, at Birmingham, 14th September, 1780. This day was Boulton’s birthday, and alluding to the circumstance he wrote,--“As sure as there are 1728 inches in a cubic foot, so sure was I born in that year; and as sure as there are 52 weeks in the year and 52 cards in the pack, so surely am I 52 years old this very day. May you and Mrs. Watt live very long and be very happy.” Watt did not give up his favourite tables without further expostulation and argument, but at length he reluctantly gave his assent to the Wheal Virgin agreement, by which the annual payment of 2500_l._ was secured. Though this was really an excellent bargain, Watt seemed to regard it in the light of a calamity. In the letter intimating his reluctant concurrence, he observed: “These disputes are so very disagreeable to me, that I am very sorry I ever bestowed so great a part of my time and money on the steam-engine. I can bear with the artifices of the designing part of mankind, but having myself no intention to deceive others, I cannot brook the suspicions of the honest part, which I am conscious I never merited even in intention, far less by any actual attempt to deceive;”[193] Two days later Watt again wrote, urging the superiority of his tables, concluding thus: “I have been so much molested with headaches this week, that I have perhaps written in a more peevish strain than I should have done if I had been in better health, which I hope you will excuse.” Boulton replied, expressing regret at his lowness of spirits and bad health, advising him to cheer up. “At your leisure,” said he, “you may amuse yourself with a calculation of what all the engines we shall have in eighteen months erected in Cornwall will amount to; you will find it good for low spirits.” “I assure you,” he said at another time, “you have no cause for apprehension as to anything in this country; all is going on well.” Boulton seemed to regard his partner in the light of a permanent invalid, which he was; and on writing to his various correspondents on matters of business at Soho, he would abjure them not to cross Mr. Watt. To Fothergill he wrote respecting the execution of an order, “the matter must be managed with some delicacy respecting Mr. Watt, as you know that when he is low-spirited he is vexed at trifles.” [193] Watt to Boulton, 10th October, 1780. Boulton MSS.