a) After working efficiently for eighteen months, the author's watch broke down. The author tried to get his watch repaired seven times by different people. When the author had given the watch to be repaired for the second time, the author got his watch back after one week. Instead of getting adjusted, the watch slowed down which resulted in the author missing his appointments and the author felt like he was going into yesterday, going even more backwards into time, feeling lonely. The author kept going back into the past and staying there because of the wrong time shown by his watch.
b) Here the author means to say that when the watch broke down after eighteen months. The chief jeweler repaired it and made it quite slow. And when he gave it to another watchmaker it made watch fairly fast. The author used symbolism when he says that the watch 'sickened to raging fever and its pulse went up to a hundred and fifty in the shade'.
c) The watch stopped after working for eighteen months. He got it repaired from seven different watchmakers. The last person to whom he gave his watch was a steam engineer, after observing the watch he said watch is making steam and that he wants to 'hang the monkey wrench on the safety valve'.