To install the service Count Atoms in the Universe:
1. Download Count Atoms in the Universe and locate the CountAtomsInTheUniverse.service file.
2. Copy it to the Services folder.
Open a new Finder window by switching to the Finder and choosing File → New Finder Window.
Navigate to the Library folder in your home folder by holding the alt/option key and then choosing Go → Library.
Inside the Library folder, open the Services folder. If it does not exist, create it.
Copy the CountAtomsInTheUniverse.service file into the Services folder.
3. Make sure it is not blocked by Gatekeeper.
Double-click the service.
An alert may appear with the text "service name can’t be opened because it is from an unidentified developer". This is a security feature in OS X. If you encounter this alert, click OK to close the dialog, then right click (or Control+click) the service and choose Open from the contextual menu. When the alert appears again, click the "Open" button to enable the service.
This is the Gatekeeper feature in OS X, warning about downloaded software without a traceable cryptographic signature being used for the first time. For more information, search Mac Help for "Gatekeeper".
✓ The Count Atoms in the Universe service is installed and can be used from applications.