#presale optimization

This last email is optional, but it tends to print money, so you may want to incorporate it.

I like to run a 20%-off launch day sale, first, to reward my early buyers for trusting me and being so eager, and secondly, to have a reason to send a reminder email at the end of the day saying that the sale is ending. A lot of people had intended to buy upon receiving the first email but, for whatever reason, didn’t. Looking at the sales hour by hour, can you tell when the second email was sent?