What are "city sevens"?

After searching Google I found this blog. It explains that City Sevens are a type of bond issued by cities that pay 7% interest.

This can be seen in this extract I found through Google Books:

Among the new securities are the city ten-per-cents, the city sevens and the city fives, the first, for $1,000,000, issued to pay pressing obligations, the second for $5,000,000, to redeem outstanding city treasury notes and the floating debt, and the third issued in payment for the water-works, agreeably to the charter of the company.


Municipal bonds with a nominal interest rate of 7%