There are many possible reasons to why your not able to make a connection between your two machines using SSH.
The university might not have a route between the two networks/subnets. In that case you will have to talk with the IT department of your university to find a solution if this is valid use. Note that often the IT department will on purpose do this to hinder users from being able to converse over the different subnets.
You can check if there is a route by trying the following:
1. ping your devices on both sides.
2. run traceroute on your IP and see where it stops.
Another reason that SSH might not work is that the IT department is blocking port 22 on their network. Forcing the SSH server to run on another port and connect to it using the new port might help.
You can check for this type of problem by using for example nmap and see which ports are open on the receiving host. If your SSH port does not appear to be open the router or gateway might be blocking the port.
AthomSfere mention that you should be able to SSH if you can ping the host. Often this is true but does not necessarily mean that it is true because they might be blocking SSH but not ping.
I hope this helps.