He decides to go to the patent office "Cigogna Franco & Co", i have marked it below with a blue arrow:
Just behind the Cathedral "Il Duomo":
Is the house still existing?
How does the house look like?
Well, let's have a look at the address:
VIA VISCONTI DI MODRONE 16?
That's Alessandro Manzoni's birthplace!!!
The patent office is still existing next door, here you can see which trademarks have been protected in the USA by Dr. Prof. Franco CIGOGNA.
(as i write this post, the last trademark registration dates Nov. 2011)