https://www.google.com/calendar/ical/edisonofficecalendar%40gmail.com/public/basic.ics
Brief instructions to subscribe using your iPhone or iPad
The most simple approach is to copy the link above and email it yourself on an account you can open on your device. Open the email, click the link and follow the instructions.
OR
Use your device’s web browser to navigate to this page.
Copy the link above
Tap the “Settings” icon on your home screen, then scroll down and select “Mail, Contacts, Calendars.”
Tap “Add Account” and select “Other.”
Select the “Add Subscribed Calendar” option, paste the Google Calendar URL in the Server box and click “Next.”
Change any settings you see fit before saving the calendar. You do not need a username or password.
Open the iCal app and tap “Calendars” in the upper left corner.
Scroll down to your subscribed calendars and make sure there is a check mark next to the Edison calendar.