What was the specific business proposal made to Damu Anna by his friend from Mumbai?

A friend of Damu Anna's from Mumbai sent him a letter with a specific business proposition concerning the cotton trade. As narrated in chapter 25, the friend suggested they buy cotton, anticipating that its price would rise instantly. He framed it as a partnership where they could make a total net profit of two lakh rupees, meaning they would each earn one lakh. The friend strongly urged Damu Anna to reply quickly and be 'smart,' describing the business as both 'clean and safe' and warning him not to let such a profitable opportunity pass by, as those who hesitate often repent later.