Theory:

     I ordered several pairs. It was very long before they came—but they were better than ever. One simply could not wear them out. And soon after that I went abroad.
 
     It was over a year before I was again in London. And the first shop I went to was my old friend’s. I had left a man of sixty; I came back to one of seventy-five, pinched and worn, who genuinely, this time, did not at first know me.
 
     “Do you wand any boods?” he said. “I can make dem quickly; id is a zlack dime.”
 
     I answered, “Please, please! I want boots all around—every kind.
Explanation:
 
The author felt pity for the bootmaker. He then ordered several pairs of boots, and they took a long time to arrive, which indicated two things to the author. Mr. Gessler would have gone weaker than before. And, since he didn't have his elder brother to help, he must have done all the work independently. Despite the time taken by Gessler, the boots designed by him were better than they had ever been. They couldn't possibly be worn down. Soon after then, the author went abroad.

The author spent over a year abroad. After returning to London, the author's first visit was to his old friend's shop (Gessler's shop). When the author left London, Mr. Gessler seemed to be a sixty-year-old man. But after a year, when he visited the Gessler's shop, he was shocked to see Gessler appearing as a seventy-five-year-old man. The younger Gessler's appearance was completely changed in a year as he seemed to be fifteen years older in just one year.
 
Gessler's aged appearance.jpg
Gessler's aged appearance

Mr. Gessler looked pinched and worn and did not recognise the author at first. The author was also taken aback when he realised Mr. Gessler had no idea who the author was.

Mr. Gessler then enquired the author if he wanted any boots? He also assured the author that he would fulfil his order as quickly as possible because he had no other clients. The author agreed to him and ordered all kinds of boots that appealed to him in the shop.
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
Appeal
A characteristic of anything that causes people to like or desire it
2.
Pinched Tired, skinny and ill in appearance
3.
WornLooking tired and strained
4.
SlackNot busy
Reference:
National Council of Educational Research and Training (2007). Honeycomb. Quality - John Galsworthy (pp. 71-78). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.